Citric acid chitosan modified waterborne polyurethane and preparation method thereof
A waterborne polyurethane and chitosan modification technology, applied in the field of modified waterborne polyurethane, can solve the problem of high cohesive energy and achieve the effect of improving biodegradability
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Embodiment 1
[0044] Step 1: the preparation of citric acid chitosan:
[0045] Weigh 3.75g of citric acid and 0.63g of sodium hypophosphite in a three-necked flask, add 50g of distilled water to it, shake it up after they are completely dissolved, then weigh 1.5g of chitosan and add it to a three-necked flask, at 105°C React for 3 hours. After the reaction, precipitate with ethanol, wash and filter with suction, place at -55°C for 36 hours in a vacuum freeze-dry, and finally grind and pulverize to obtain powdered citrated chitosan;
[0046] Step 2: Add 30g of dried polytetrahydrofuran ether glycol (PTMG-2000) and 16.7g of isophorone diisocyanate (IPDI) into a three-necked flask, stir evenly, and drop 0.023g of dibutyltin dilaurate (DBTDL) , react at 80°C for 2h; adjust the temperature to 75°C, add 2.3g of dimethylolpropionic acid (DMPA) and 0.93g of 1,4-butanediol (BDO), and continue the reaction for 3h; add absolute ethanol 1.6 g for capping, and react at 70°C for 30 minutes to obtain par...
Embodiment 2
[0050] Step 1: Preparation of Citrated Chitosan
[0051] Weigh 4.5g of citric acid and 0.5g of sodium hypophosphite in a three-necked flask, add 50g of distilled water to it, shake it up after they are completely dissolved, then weigh 1.5g of chitosan and add it to a three-necked flask, at 110°C React for 3 hours. After the reaction, precipitate with ethanol, wash and filter with suction, place at -55°C for 36 hours in a vacuum freeze-dry, and finally grind and pulverize to obtain powdered citrated chitosan;
[0052] Step 2: Add 30g of dried polytetrahydrofuran ether glycol (PTMG-2000) and 20g of isophorone diisocyanate (IPDI) into a three-necked flask, stir evenly, and dropwise add a mass fraction of 0.03g of dibutyltin dilaurate ( DBTDL), reacted at 80°C for 2h; adjusted the temperature to 75°C, added 2.5g dimethylolpropionic acid (DMPA) and 1.0g 1,4-butanediol (BDO), and continued to react for 3h; added anhydrous Block with 2.2g of ethanol and react at 70°C for 30 minutes ...
Embodiment 3
[0056] Step 1: Preparation of Citrated Chitosan
[0057] Weigh 5.3g of citric acid and 0.88g of sodium hypophosphite in a three-necked flask, add 50g of distilled water to it, shake it up after they are completely dissolved, then weigh 1.5g of chitosan and add it to a three-necked flask, at 110°C React for 2.5 hours. After the reaction, precipitate with ethanol, wash and filter with suction, place at -55°C for 36 hours in a vacuum freeze-dry, and finally grind and pulverize to obtain powdered citrated chitosan;
[0058] Step 2: Add 30g of dried polytetrahydrofuran ether glycol (PTMG-2000) and 13.3g of isophorone diisocyanate (IPDI) into a three-necked flask, stir evenly, and drop 0.017g of dibutyltin dilaurate (DBTDL) , react at 80°C for 2h; adjust the temperature to 75°C, add 2.2g dimethylolpropionic acid (DMPA) and 0.86g 1,4-butanediol (BDO), and continue the reaction for 3h; add absolute ethanol 1.0 g for capping, and react at 70°C for 30 minutes to obtain partially blocke...
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