Polylactic acid/starch whole biological-base composite material and preparation method of composite material

[0039] Preparation of D-polylactic acid polyurethane elastomer:

[0040] First, the prepolymer is obtained by reacting D-polylactide polyol (number average molecular weight: 2000), isophorone diisocyanate and dibutyltin dilaurate catalyst at 85°C for 2 hours under the protection of protective gas (nitrogen) , and then add the chain extender 1,4-butanediol to carry out the chain extension reaction for 4h, and remove the solvent after the reaction to obtain the dextrolactide polyol polyurethane elastomer (ie, the dextrolactide polyol polyurethane elastomer). The molar ratio of D-polylactide polyol, isophorone diisocyanate and 1,4-butanediol chain extender is 1:3:2, dibutyltin dilaurate catalyst and D-polylactide The molar ratio of ester polyol is 0.005:1.

[0042]Get the prepared D-polylactic acid polyurethane (5 parts by mass), polylactic acid (the number-average molecular weight of polylactic acid is 150000, and its parts by mass is 85) and cornstarch (10 parts by mass) and mix evenly (first in the initial The temperature is pre-mixed at 40°C, the pre-mixer is slowly increased from a low speed of 800 rpm to a high speed of 1200 rpm, and mixed for 30 minutes), melted and blended in a twin-screw extruder, and the extrusion temperatures of the first to sixth stages are sequentially 175°C±5, 180°C±5, 185°C±5, 190°C±5, 180°C±5, 180°C±5, after the extrudate is cooled, it is pelletized by a granulator to obtain pellets, and the pellets The material was dried in a vacuum drying oven at 85° C. for 12 hours to obtain dextrorotatory polylactic acid polyurethane / polylactic acid / starch composite pellets. According to GB / T1040.1-2006 and ISO 179-1:98, the toughened and heat-resistant polylactic acid / starch composite material of D-polylactic ...

[0044] Get the prepared D-polylactic acid polyurethane (5 parts by mass), polylactic acid (the number-average molecular weight of polylactic acid is 150000, and its parts by mass is 75) and cornstarch (20 parts by mass) after mixing evenly (first in the initial The temperature is pre-mixed at 40°C, the pre-mixer is slowly increased from a low speed of 800 rpm to a high speed of 1200 rpm, and mixed for 30 minutes), melted and blended in a twin-screw extruder, and the extrusion temperatures of the first to sixth stages are sequentially 175°C±5, 180°C±5, 185°C±5, 190°C±5, 180°C±5, 180°C±5, after the extrudate is cooled, it is pelletized by a granulator to obtain pellets, and the pellets The material was dried in a vacuum drying oven at 85° C. for 12 hours to obtain dextrorotatory polylactic acid polyurethane / polylactic acid / starch composite pellets. According to GB / T1040.1-2006 and ISO 179-1:98, the toughened and heat-resistant polylactic acid / starch composite material of D-polyl...