Study On Blending Modification Of P(3HB-co-4HB)/Pla/Starch

P(3HB-co-4HB), PLA. and starch were selected as raw materials, and epoxy soybean oil (ESO), triethyl citrate (TEC), dioctyl phthalatc (DOP) and Polyethylene glycol (PEG) with different molecular weight were used as plasticizers to prepare P(3HB-co-4HB)/PLA/starch blends. Differential scanning calorimetry (DSC), electronic tensioner, scanning electron microscopy (SEM), capillary rheometer and vicat heat distortion temperature tester were used to characteristize the effects of different types and dosages of plasticizers on the P(3HB-co-4HB)/PLA/starch blends and investigate thermal performance, mechanical properties, cross-section morphology, and rheological properties. P(3HB-co-4HB) and maleic anhydride (MAH) were selected to prepare P(3HB-co-4HB)-g-MAH grafting copolymer by microwave irritation. The hydrophilicity, crystalline morphology, melting point (Tm) and mechanical properties of P(3HB-co-4HB)/PLA/starch blends were studied by contact angle tester, hot stage polarizing microscopy(PLM), DSC, fourier transform infrared spectroscopy (FTIR) and electronic tensioner.The results show that:(1) Mobility and elongation at break of the P(3HB-co-4HB)/PLA/starch blends could be effectively improved by the types of plasticizers. The plasticization effect of ESO is better than TEC and DOP, and the comprehensive properties of the blends are the best at the dosage of ESO is10percent. The plasticization effects of PEG with10,000molecular weight is much better than that of PEG with1000or4000molecular weight, and when the dosage of PEG with10,000molecular weight is7percent, The comprehensive properties of blends is the best.(2) The grafting reaction of MAH onto P(3HB-co-4HB) could be carried out under microwave irritation and grafting ratios from0.3%to0.78%could be obtained. The highest grafting ratio reached to0.78%at BPO and MAH are0.2percentr and4percent as well as microwave irritation time is12mins, which are the best reaction conditions. The higher grafting ratio, the finer spherulite size, the better hydrophilic and lower melting temperature of P(3HB-co-4HB)-g-MAH. Compatibilizer P(3HB-co-4HB)-g-MAH is added to improve the mechanical properties and interface compatibility of P(3HB-co-4HB)/PLA/starch blends, of which the dosage is2percen, the comprehensive properties of blends is the best.