Preparation Of PBAT/Starch Composites And Its Degradation Mechanism And Comprehensive Performance Study

The application of degradable polymer polybutylene terephthalate(PBAT)is of great significance to environmental protection and social development.Meanwhile,with the progress of society,there is higher requirements on the cost,degradability,mechanical properties and multifunctionality of PBAT,so the research on PBAT composites is important.Aiming to reduce the production cost and improving the comprehensive performance of PBAT composites,this work established and explained the corresponding scheme,which provided technical and theoretical support for the development and exploitation of PBAT.The main research results and innovations were summarized as follows:1.A new class of low eutectic solvents(DESs)containing choline chloride was designed as plasticizers for the problem of strong intermolecular chain interaction of starch,and the prepared thermoplastic starch(TPS)realized the improvement of mechanical properties and comprehensive performance.The crystallinity of TPS after plasticization with choline chloride-thiourea(CHClTU)and choline chloride-glycerol(CHCl-Gly)decreased by 56.2% and 54.6%,compared to TPS-W,respectively.There was no regrowth after three months CHCl-TU and CHCl-Gly.In the light transmission test,TPS-CHCl-Gly and TPS-CHCl-TU was increased by 82.4% and 63.7% at 660 nm compared to that of TPS-W,and TPS-CHCl-TU showed UV blocking.The tensile strength of TPS-CHCl-TU and TPS-CHCl-Gly was increased to 3.0 MPa and 2.9 MPa,respectively,and the elongations at break was increased to 26.7% and 24.6%,respectively.The surface hydrophilicity,solubility,thermal stability and degradation rate of TPS was also improved for CHCl-Gly and CHCl-TU samples.The limiting oxygen index(LOI)for TPS-CHCl-TU was 31.4,and passed V-0 rating,peak of heat release rate(p HRR)was decreased by 29.2%compared to that of TPS-Gly.Compared to the traditional plasticizer,the operation for CHCl-TU and CHCl-Gly as plasticizer plasticizing starch were simple,and mechanical properties and other comprehensive performance was improved greatly.2.The preparation of inexpensive and rapidly degradable PBAT composites is the require for the environmental protection and production development.The composites prepared by using DESs plasticized starch as the filler of PBAT achieved enhanced mechanical properties,improved light transmission and faster degradation rate.The tensile strength for PBAT/Starch/CHCl-Gly and PBAT/Starch/CHCl-TU increased from 6.7 MPa to 7.9 MPa and 7.8 MPa,and elongation at break increased from 125.5% to335.6% and 291.1% when choline chloride-glycerol(CHCl-Gly)and(CHCl-TU)as PBAT/starch plasticizers.The light transmission at 660 nm increased to 56.9% and 53.8% respectively.The water contact angle of the composites decreased from 71° to 54° and 48°,and the water absorption rate increased from 8.8% to 23.6% and 27.5%.The addition of CHCl-Gly and CHCl-TU accelerated the degradation rate of PBAT/starch composites in simulated compost degradation tests.The introduction of DESs provided a new idea for the plasticization and preparation of PBAT composites.3.In order to further improve the mechanical and degradation properties of PBAT/starch composites,a three-layer structured composite film material was prepared.PBAT/starch composites were used as the outer layer and thermoplastic starch as the inner layer to prepare the composites film.The tensile strength and elongation at break of the film was decreased with the increasing thickness of the TPS layer.The tensile strength and elongation at break was increased to 11.8 MPa and 469% for PTP-8 compared to that of 15.8 MPa and648% for PTP-0.Meanwhile,the degradation rate of the films was accelerated,and the degradation rate of PTP-8 reached 72.1% after 45 days,but that of PTP-0 was just 19.3%.The crystallization and morphology observation showed the same law.This work was important for accelerating the degradation of PBAT composites and reducing the preparation of environmentally polluting materials.