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472 lines
25 KiB
HTML
472 lines
25 KiB
HTML
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<title>hemp bioplastic process — unturf.</title>
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<main class="content-wide">
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<center><a href="/"><h1 class="site-title">unturf.</h1></a></center>
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<center><h3>grow food not lawn</h3></center>
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<center class="nav-links"><small><a href="/let-us-define-a-permacomputer/">manifesto</a> · <a href="/eight-forms-of-capital/">eight forms of capital</a> · <a href="/single-use-plastics/">single-use plastics</a> · <a href="/hemp-bioplastic/">hemp bioplastic</a> · <a href="/hemp-bioplastic/process/" aria-current="page">recipe</a> · <a href="/software/">free software</a></small></center>
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<h2>Hemp Bioplastic: Process</h2>
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<p>
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A step-by-step recipe for turning hemp stalks into bioplastic. Three approaches exist — from full cellulose extraction (most chemistry) to citric acid crosslinking (least chemistry). This page covers all three with exact quantities, temperatures, times, & safety notes.
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</p>
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<p>
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Start with a 50g test batch. Expect 2-3 days from stalk to finished object. Expect to fail the first time. Expect to learn why.
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</p>
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<!-- ============================================================ -->
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<!-- PLANT ANATOMY -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 1</span>
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<h3>Which Parts of Hemp We Harvest</h3>
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<p>
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Hemp bioplastic comes from <b>stalks only</b> — specifically bast fiber, the outer bark layer of the main stem. Not leaves. Not seeds. Not roots. Each part serves a different purpose.
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</p>
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<figure class="diagram">
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<img src="img/plant-anatomy.svg" alt="Hemp plant anatomy: which parts we use for bioplastic">
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<figcaption>bioplastic comes from stalk bast fiber. everything else serves other purposes.</figcaption>
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</figure>
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<table>
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<thead>
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<tr><th>Plant Part</th><th>Use for Bioplastic?</th><th>What It Does Instead</th></tr>
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</thead>
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<tbody>
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<tr><td><b>Stalk — bast fiber</b></td><td>Yes — primary source</td><td>77% cellulose, highest quality</td></tr>
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<tr><td><b>Stalk — hurd (core)</b></td><td>Yes — lower grade</td><td>44% cellulose, or use for hempcrete, animal bedding, garden mulch</td></tr>
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<tr><td>Leaves</td><td>No</td><td>Compost, mulch, animal feed</td></tr>
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<tr><td>Seeds</td><td>No</td><td>Food (hemp hearts), oil, or save for next crop</td></tr>
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<tr><td>Roots</td><td>No</td><td>Stay in ground — improve soil structure, break compaction, add organic matter</td></tr>
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<tr><td>Flowers</td><td>No</td><td>Fiber varieties produce minimal flower; if present, compost or dry</td></tr>
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</tbody>
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</table>
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<p>
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Harvest stalks when they reach full height (2-4 meters, ~120 days). Cut at ground level. Leave roots in soil — they decompose & feed next season's crop. Strip leaves & set aside for compost. Collect seeds if needed for replanting.
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</p>
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<!-- ============================================================ -->
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<!-- THREE APPROACHES -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 2</span>
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<h3>Three Approaches</h3>
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<p>
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No single canonical recipe exists. Research reveals three distinct paths, each with different tradeoffs between chemistry complexity & material quality.<sup id="ref1"><a href="#fn1">[1]</a></sup>
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</p>
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<figure class="diagram">
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<img src="img/three-approaches.svg" alt="Three approaches: cellulose extraction, fiber composite, citric acid crosslinking">
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<figcaption>pick your path based on equipment, chemistry comfort, & desired result.</figcaption>
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</figure>
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<table>
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<thead>
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<tr><th>Approach</th><th>Chemistry</th><th>Time</th><th>Strength</th><th>Best For</th></tr>
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</thead>
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<tbody>
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<tr><td>A: Cellulose extraction</td><td>NaOH + acid + bleach</td><td>2-3 days</td><td>2-7 MPa</td><td>Pure bioplastic objects</td></tr>
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<tr><td>B: Fiber + bioresin</td><td>Seaweed + starch (no NaOH)</td><td>1 day</td><td>Moderate</td><td>Panels, flat sheets</td></tr>
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<tr><td>C: Citric acid crosslink</td><td>Citric acid + glycerol (no NaOH)</td><td>1 day</td><td>Up to 70 MPa</td><td>Strongest result, safest chemistry</td></tr>
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</tbody>
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</table>
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<div class="recipe-box">
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<b>Recommendation for first attempt:</b> Approach C (citric acid crosslinking) avoids all NaOH, all acid work, & all bleaching while producing material up to 70 MPa tensile strength.<sup id="ref5"><a href="#fn5">[5]</a></sup> If you want to understand full cellulose extraction, try Approach A on a second batch.
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</div>
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<!-- ============================================================ -->
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<!-- EQUIPMENT -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 3</span>
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<h3>Equipment</h3>
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<figure class="diagram">
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<img src="img/equipment.svg" alt="Equipment needed for a 50g test batch">
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<figcaption>total equipment cost: $500-2,000 for basic workshop setup.</figcaption>
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</figure>
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<h4>Chemistry (Approach A only)</h4>
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<ul>
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<li>Stainless steel pot, 2-5 liter — <b>NOT aluminum</b> (reacts with NaOH)</li>
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<li>Hot plate capable of 80-100°C</li>
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<li>Digital thermometer, 0-200°C range</li>
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<li>pH strips, range 1-14</li>
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<li>Vacuum filtration: Buchner funnel + vacuum flask + water aspirator</li>
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<li>Kitchen scale, 0.1g precision</li>
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<li>Mortar & pestle or coffee grinder for fiber size reduction</li>
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<li>Metal sieve, 1.5mm mesh</li>
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<li>Multiple large buckets for washing</li>
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</ul>
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<h4>Pressing (all approaches)</h4>
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<ul>
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<li>Metal mold — aluminum soap mold works for test batches</li>
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<li>Oven capable of 140-200°C, or a rosin press ($200-500)</li>
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<li>Bench vise, hydraulic press, or heavy C-clamps for pressure</li>
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<li>Heat-resistant gloves rated 200°C+</li>
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</ul>
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<h4>Safety (non-negotiable)</h4>
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<ul>
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<li>Chemical splash goggles — not just safety glasses</li>
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<li>Nitrile gloves, elbow length</li>
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<li>Ventilated workspace — fume hood or work outdoors</li>
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<li>Bottle of 2% vinegar nearby for NaOH spill neutralization</li>
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<li>Running water within arm's reach</li>
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</ul>
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<!-- ============================================================ -->
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<!-- RETTING -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 4</span>
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<h3>Retting (Preparing Stalks)</h3>
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<p>
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Before separating fiber from stalk, retting partially breaks down the pectin that binds bast fiber to hurd. Skip this & decortication becomes very difficult.<sup id="ref12"><a href="#fn12">[12]</a></sup>
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</p>
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<figure class="diagram">
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<img src="img/retting-test.svg" alt="Retting process and three tests to check readiness">
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<figcaption>dew retting takes 3-45 days depending on temperature. three tests confirm readiness.</figcaption>
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</figure>
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<h4>Dew Retting (simplest)</h4>
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<ol>
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<li>Lay harvested stalks on grass, exposed to rain & dew</li>
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<li>Turn stalks every few days for even breakdown</li>
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<li>Maintain ~30% moisture — sprinkle with water if dry</li>
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<li>Duration depends on temperature:
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<ul>
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<li>37°C → 3 days</li>
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<li>20°C → 7-8 days</li>
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<li>12°C → 15-17 days</li>
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<li>7°C → 30-45 days</li>
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<li>Below 5°C → retting stops</li>
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</ul>
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</li>
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</ol>
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<h4>Water Retting (faster)</h4>
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<ol>
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<li>Submerge stalks in warm water for ~10 days</li>
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<li>Change water periodically — it will smell</li>
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<li>Bacteria in water accelerate pectin breakdown</li>
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</ol>
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<h4>Three Tests for Readiness</h4>
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<div class="recipe-box">
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<b>Bend test:</b> Bend dried stalks back & forth. Hurd should crack & fall free. Fiber should NOT break when shaken.<br><br>
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<b>Peel test:</b> Peel fiber at base of stem. Should separate easily for several inches. If fiber breaks after a few inches, retting needs more time.<br><br>
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<b>Color test:</b> Fiber bundles turning white signals readiness.
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</div>
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<div class="warning-box">
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<b>Over-retting weakens fiber.</b> Under-retting makes separation very difficult. Test every 2-3 days. When in doubt, under-ret — you can always ret longer but cannot un-ret.
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</div>
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<!-- ============================================================ -->
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<!-- DECORTICATION -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 5</span>
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<h3>Decortication (Separating Fiber)</h3>
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<p>
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After retting, separate bast fiber from hurd by hand.<sup id="ref9"><a href="#fn9">[9]</a></sup> Target: 95% clean bast fiber with 5% or less hurd contamination.
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</p>
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<ol>
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<li><b>Break:</b> Bend & snap dried retted stalks repeatedly. Woody hurd should crack & fall away from flexible bast fiber.</li>
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<li><b>Shake:</b> Shake vigorously to dislodge hurd fragments.</li>
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<li><b>Scutch:</b> Beat fibers against a hard surface to remove remaining hurd.</li>
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<li><b>Hackle:</b> Pull fibers through coarse wire brushes or metal combs to remove short fibers & debris.</li>
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</ol>
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<p>
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For fresh (un-retted) stalks: use a knife at the base to separate the green outer fiber layer from the woody core. Peel bast fiber upward toward the tip. Slower but works without retting.
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</p>
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<!-- ============================================================ -->
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<!-- APPROACH A: CELLULOSE EXTRACTION -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 6</span>
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<h3>Approach A: Cellulose Extraction</h3>
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<p>
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Full chemical extraction produces the purest cellulose. Three protocols exist — start with Protocol 2 (gentlest) for a first attempt.<sup id="ref1b"><a href="#fn1">[1]</a></sup>
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</p>
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<figure class="diagram">
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<img src="img/cellulose-extraction.svg" alt="Cellulose extraction process: prepare, alkali treat, bleach, purify">
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<figcaption>50g hemp powder yields ~25g pure cellulose through 4 stages.</figcaption>
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</figure>
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<h4>Size Reduction</h4>
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<ol>
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<li>Dry separated bast fibers at 50°C until constant weight</li>
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<li>Cut to 2-3 cm lengths</li>
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<li>Grind using blender, coffee grinder, or mortar & pestle</li>
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<li>Pass through 1.5mm metal sieve</li>
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<li>Weigh 50g of powder (test batch)</li>
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</ol>
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<h4>Protocol 1: Full Extraction (highest purity)</h4>
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<div class="recipe-box">
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<b>Alkali treatment:</b><sup id="ref2"><a href="#fn2">[2]</a></sup><br>
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50g hemp powder + 750 mL of 12% NaOH solution (= 90g NaOH pellets dissolved in 750 mL water). Solid/liquid ratio 1:15. Heat to 80°C with continuous stirring at 500 rpm. Hold for 3 hours. Vacuum filter. Wash with deionized water 4-5 times until wash water reaches neutral pH. Dry at 60°C overnight.<br><br>
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<b>Bleaching (optional but recommended):</b><sup id="ref3"><a href="#fn3">[3]</a></sup><br>
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8% hydrogen peroxide solution, pH adjusted to 12 with NaOH. 40°C, solution/solid ratio 30:1. 1 hour per cycle, repeat 4 cycles. Wash until neutral. Safer than sodium chlorite for workshop use.<br><br>
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<b>Hemicellulose removal:</b><br>
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Treat bleached product with 17.5% NaOH solution. Room temperature. 5 hours with continuous stirring at 500 rpm. Vacuum filter. Wash 3 times with deionized water. Dry at 60°C overnight.
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</div>
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<h4>Protocol 2: Gentle Extraction (best for beginners)</h4>
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<div class="recipe-box">
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<b>Alkali treatment:</b><sup id="ref6"><a href="#fn6">[6]</a></sup><br>
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5% NaOH solution (= 50g NaOH per liter of water). Soak hemp fibers at room temperature (23°C) for 4 hours. No heating required. Wash with tap water until pH ~7. Oven dry at 80°C until constant weight.<br><br>
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This protocol found 5% NaOH for 1 hour nearly as effective as 4 hours. Start with 1 hour, check results, extend if needed.
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</div>
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<div class="warning-box">
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<b>NaOH safety.</b> ALWAYS add NaOH pellets to water, NEVER water to NaOH. Dissolution generates heat & can spatter violently. At 12-17.5% concentration, NaOH solution dissolves skin on contact. Wear splash goggles & elbow-length nitrile gloves. Keep running water within arm's reach. If skin contact occurs, flush with water for 15+ minutes. Store NaOH pellets in airtight containers — they absorb moisture from air.
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</div>
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<!-- ============================================================ -->
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<!-- APPROACH B: BIORESIN COMPOSITE -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 7</span>
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<h3>Approach B: Fiber + Bioresin Composite</h3>
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<p>
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Robert Murray-Smith's method skips all chemical extraction.<sup id="ref4"><a href="#fn4">[4]</a></sup> Instead, hemp fiber acts as reinforcement inside a bioresin matrix made from seaweed & corn starch.
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</p>
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<div class="recipe-box">
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<b>Bioresin recipe:</b><br>
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25g dried seaweed (carrageenan or agar) + 50g corn starch + 1 liter water. Heat & stir until dissolved into a viscous liquid.<br><br>
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<b>Process:</b><br>
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1. Prepare a hemp fiber mat (loose fiber spread into a flat layer)<br>
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2. Pour bioresin over fiber mat<br>
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3. Roll with a roller until resin penetrates fully through the mat<br>
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4. Dry in oven at 150-200°C for 20 minutes<br>
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5. Result: a rigid composite panel<br><br>
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<b>Variant:</b> Replace seaweed/starch with casein (milk protein) + tannin (from strong tea or chestnut extract) for a harder result. Murray-Smith describes this as "quite hard, quite plastic."
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</div>
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<p>
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This produces a composite — not pure bioplastic. Hemp fiber (30-50% by weight) reinforces a starch or protein matrix. Simpler chemistry, fewer hazards, one-day process. Tradeoff: less versatile shapes, works best for flat panels & sheets.
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</p>
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<!-- ============================================================ -->
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<!-- APPROACH C: CITRIC ACID CROSSLINKING -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 8</span>
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<h3>Approach C: Citric Acid Crosslinking</h3>
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<p>
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Developed by Beluns et al. at Riga Technical University (2023).<sup id="ref5b"><a href="#fn5">[5]</a></sup> No NaOH. No acid baths. No bleach. Produces material up to 70 MPa tensile strength — comparable to commodity petroleum plastics. The safest & strongest approach.
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</p>
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<div class="recipe-box">
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<b>Process:</b><br>
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1. Chop hemp stalks (bast + hurd together works) & soak in water<br>
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2. Spread fibers on a screen, press flat, dry — making a rough hemp paper<br>
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3. Prepare impregnation solution: 2g glycerol + 1g citric acid + small amount of PEG (polyethylene glycol), dissolved in minimal water<br>
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4. Soak hemp paper in solution until saturated<br>
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5. Place on a metal sheet, cover with another sheet<br>
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6. Cure at 140°C in oven for 30-60 minutes under weight (a brick or cast iron pan on top)<br>
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7. Wash in water for 24-48 hours to remove unreacted material<br>
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8. Dry at room temperature
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</div>
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<p>
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Tradeoff: requires xylan (hemicellulose powder) & PEG (polyethylene glycol) — specialty chemicals, but non-hazardous & available from lab suppliers online. The citric acid crosslinks cellulose chains, creating thermal bonds that reduce water uptake 7-fold versus untreated hemp paper. These bonds reverse at high temperature, making the material theoretically recyclable by re-heating.
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</p>
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<!-- ============================================================ -->
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<!-- MIXING & PRESSING -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 9</span>
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<h3>Mixing & Hot Pressing (Approach A)</h3>
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<p>
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After extracting cellulose via Approach A, mix with plasticizer & press into shapes.
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</p>
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<figure class="diagram">
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<img src="img/pressing.svg" alt="Mixing cellulose with glycerol and hot pressing into molds">
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<figcaption>the material MUST be completely dry before pressing. this is the most common failure point.</figcaption>
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</figure>
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<div class="recipe-box">
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<b>Mixing:</b><br>
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1. Weigh dried cellulose<br>
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2. Add glycerol: 15% by weight for rigid, 30% for flexible<br>
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3. Add water to make a workable slurry<br>
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4. Stir at 80°C for 60 minutes until homogeneous<br>
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5. Optional: add 5% citric acid by weight for water resistance<br><br>
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<b>Drying (critical):</b><br>
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6. Spread mixture on a tray<br>
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7. Dry at 60°C overnight — or until weight stabilizes<br>
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8. Grind to a breadcrumb/sawdust consistency<br><br>
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<b>Pressing:</b><sup id="ref11"><a href="#fn11">[11]</a></sup><br>
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9. Coat mold interior with thin layer of vegetable oil<br>
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10. Fill mold with dry material, compress lightly by hand, add lid<br>
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11. Heat to 150°C (oven or heat press)<br>
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12. Once at temperature, apply maximum pressure — bench vise, hydraulic press, or C-clamps<br>
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13. Hold at temperature & pressure for 10-30 minutes (30 min gave best strength in testing)<br>
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14. Release pressure<br>
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15. Cool slowly in mold — do not rush, rapid cooling causes cracking<br>
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16. Demold
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</div>
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<div class="warning-box">
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<b>If material stays wet when pressed:</b> Steam creates voids. Result becomes spongy & porous. This represents the most common failure mode. Murray-Smith emphasizes: "if it's wet and you heat it and press it, you'll press off a lot of steam and it won't form properly."<sup id="ref4b"><a href="#fn4">[4]</a></sup> Dry overnight. Verify weight has stopped changing. Then press.
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</div>
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<!-- ============================================================ -->
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<!-- TROUBLESHOOTING -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 10</span>
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<h3>Troubleshooting</h3>
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<figure class="diagram">
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<img src="img/troubleshooting.svg" alt="Common problems and solutions">
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<figcaption>every failure teaches something. expect the first batch to teach more than it produces.</figcaption>
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</figure>
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<h4>Quality Indicators</h4>
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<table>
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<thead>
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<tr><th>Check</th><th>Good</th><th>Bad</th></tr>
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</thead>
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<tbody>
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<tr><td>Color after extraction</td><td>White to off-white</td><td>Brown/yellow (lignin remains)</td></tr>
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<tr><td>Texture when dry</td><td>Fibrous, fluffy, crumbly</td><td>Stiff hard chunks (hurd contamination)</td></tr>
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<tr><td>Weight loss from original</td><td>40-50% for bast (normal)</td><td>>70% (over-treated) or <30% (under-treated)</td></tr>
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<tr><td>Surface after pressing</td><td>Smooth, glossy</td><td>Rough, porous, bubbled (wet)</td></tr>
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<tr><td>Sound when tapped</td><td>Solid "click"</td><td>Hollow "thud" (voids inside)</td></tr>
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<tr><td>Water drop test</td><td>Water beads or absorbs slowly</td><td>Instantly absorbs & softens (needs crosslinking)</td></tr>
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</tbody>
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</table>
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<!-- ============================================================ -->
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<!-- SCALING -->
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<!-- ============================================================ -->
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<span class="step-label">STEP 11</span>
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<h3>Scaling Up</h3>
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<table>
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<thead>
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<tr><th>Scale</th><th>Input</th><th>Yield</th><th>Time</th><th>Notes</th></tr>
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</thead>
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<tbody>
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<tr><td>Test batch</td><td>50g bast fiber</td><td>~25g cellulose</td><td>2-3 days</td><td>One soap-mold-sized object. $5-10 in chemicals.</td></tr>
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<tr><td>Useful batch</td><td>2 kg bast fiber</td><td>~1 kg cellulose</td><td>3-5 days</td><td>10-20 liter reaction vessel needed. ~100+ liters wash water.</td></tr>
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<tr><td>Community batch</td><td>20 kg bast fiber</td><td>~10 kg cellulose</td><td>5-7 days</td><td>Needs mechanical stirring, larger press, waste handling plan.</td></tr>
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</tbody>
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</table>
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<div class="warning-box">
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<b>Scaling NaOH:</b> Dissolution stays exothermic. At larger volumes, add pellets slowly & monitor temperature. A 20-liter NaOH batch generates significant heat. Never dump all pellets at once.
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</div>
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<p>
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Approach C (citric acid crosslinking) scales most easily — no chemical extraction means no waste liquor management. Just make more hemp paper, apply more solution, cure in a larger oven. A community could run this with minimal training.
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</p>
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<hr>
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<h3>Honest Summary</h3>
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<p>
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Making hemp bioplastic at home stays possible but labor-intensive. A 50g test batch costs $5-10 in chemicals & takes 2-3 days. Results will vary. First batches teach more than they produce. Approach C (citric acid) offers the safest entry point with the strongest results. Approach A (full extraction) teaches the most about cellulose chemistry. Approach B (bioresin composite) produces useful panels fastest.
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</p>
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<p>
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None of this replaces buying groceries in glass jars or using cloth bags — those remain easier. But for seed trays, plant pots, serving ware, & packaging where you want a compostable container made from your own land, this process closes a cycle. Grow it. Process it. Use it. Compost it. Grow again.
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</p>
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<hr>
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<h3>Sources</h3>
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<div class="footnotes">
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<ol>
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<li id="fn1">Chalannavar et al. (2025), "Industrial Cannabis sativa: Hemp Cellulose Based Bioplastic Production," <a href="https://magnascientiapub.com/journals/msabp/sites/default/files/MSABP-2025-0067.pdf" target="_blank">Magna Scientia</a>. Comprehensive review reproducing Liao protocol with 50g/12% NaOH/1:15 ratio/80°C/3h parameters. <a href="#ref1">↩</a></li>
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<li id="fn2">Liao (2022), <a href="https://escholarship.mcgill.ca/downloads/cz30pz65p.pdf" target="_blank">McGill University thesis</a>. Hemp nanocellulose extraction: 49.6% yield from bast fiber at 97% purity. Detailed NaOH protocol with exact quantities. <a href="#ref2">↩</a></li>
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<li id="fn3">Hydrogen peroxide bleaching protocol from <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC10611065/" target="_blank">PMC 10611065</a>. Safer alternative to sodium chlorite for workshop-scale cellulose bleaching. <a href="#ref3">↩</a></li>
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<li id="fn4">Robert Murray-Smith, <a href="https://www.youtube.com/watch?v=UCuPwBYyYKE" target="_blank">"A Hemp And Seaweed Bioplastic"</a> (2020) & <a href="https://www.youtube.com/watch?v=REqqJOaE30U" target="_blank">"Hot Press Molding Hemp Casein Plastic"</a> (2020). Workshop demonstrations with bioresin composite & casein-tannin approaches at 150°C. <a href="#ref4">↩</a></li>
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<li id="fn5">Beluns et al. (2023), "Sustainable hemp-based bioplastics with tunable properties via reversible thermal crosslinking of cellulose," <a href="https://pubmed.ncbi.nlm.nih.gov/37245763/" target="_blank"><i>Int J Biol Macromol</i></a>. No chemical pretreatment, citric acid crosslinking at 140°C, achieving up to 70 MPa tensile strength & 7-fold water uptake reduction. <a href="#ref5">↩</a></li>
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<li id="fn6">Dhakal et al. (2022), <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC9182753/" target="_blank">PMC 9182753</a>. 5% NaOH treatment of hemp at room temperature for 1-4 hours — gentlest effective protocol. <a href="#ref6">↩</a></li>
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<li id="fn7"><a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC12073554/" target="_blank">PMC 12073554</a> (2025). Hemp waste cellulose extraction via alternating 2% NaOH & 1M HCl treatments. Milder protocol with 47% yield. <a href="#ref7">↩</a></li>
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<li id="fn8"><a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC5456901/" target="_blank">PMC 5456901</a>. Abraham et al. (2016), hemp hurd cellulose microfiber extraction via alkaline & acid hydrolysis. <a href="#ref8">↩</a></li>
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<li id="fn9">Hemp In A Pot, <a href="https://www.youtube.com/watch?v=iywsYqBxrPY" target="_blank">"Manual Decortication of Hemp Stalks By Hand"</a> (2020). Practical video demonstration of hand decortication. <a href="#ref9">↩</a></li>
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<li id="fn10">Solis Garcia et al. (2025), <a href="http://scielo.senescyt.gob.ec/scielo.php?pid=S2477-91052025000100024&script=sci_abstract&tlng=en" target="_blank">"Extraction of cellulose fibers from hemp stalk by chemical treatment"</a>. Optimal at 10% NaOH / 120 min yielding 75.11% alpha-cellulose. <a href="#ref10">↩</a></li>
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<li id="fn11"><a href="https://bio-protocol.org/exchange/minidetail?id=21294617&type=30" target="_blank">Bio-protocol</a> (2025). Hemp cellulose + glycerol + NaOH, stirred 60 min at 80°C, hot pressed at 240°C for 10 min. <a href="#ref11">↩</a></li>
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<li id="fn12">Robert A. Nelson, <a href="http://www.rexresearch.com/hhusb/hh3fiber.htm" target="_blank">"Hemp Husbandry, Chapter 3: Hemp Fiber"</a>. Comprehensive retting reference with temperature/duration data. <a href="#ref12">↩</a></li>
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</ol>
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</div>
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<hr>
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<p><a href="/hemp-bioplastic/">← hemp bioplastic overview</a> · <a href="/hemp-bioplastic/process/homeschool/">homeschool recipe</a> · <a href="/hemp-bioplastic/process/factory/">factory</a> · <a href="/single-use-plastics/">single-use plastics</a> · <a href="/let-us-define-a-permacomputer/">manifesto</a></p>
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