Preparation of bio-based plastics from dissolved wood flour in DMSO/TEAC solvent system
GUAN Yating;YE Judi;LI Xiaobao;HONG Jianguo;Nanjing Forestry University,College of Biology and the Environment;
Injection-moulded bio-based plastics were prepared using mulberry branch as the rawmaterial. The dimethyl sulfoxide/tetraethylammonium chloride(DMSO/TEAC) solvent was used to dissolve and precipitate ball-milled wood powder and at the same time to plasticize the wood material. During the modification process,the TEAC could gradually penetrate into the cellulose molecular chains,and(C2 H5)4 N+and Cl-would form coordination bonds and hydrogen bonds with the hydroxyl groups of cellulose,therefore would prevent the formation of hydrogen bonds between cellulose molecular chains. The modified product possessed properties of thermoplastic and finally the injectiongrade bio-based plastic was prepared. The product was extruded with a certain amount of glycerol triacetate to improve its mechanical properties. The effects of the mass ratio of the TEAC to DMSO,screwspeed,extrusion temperature and glycerol triacetate content on the tensile and flexural strength of the bio-based plastics were studied. The results showed that the plastic products cannot be molded under either extreme high or lowscrewspeed and extrusion temperature. The optimum preparation conditions were as follows: the mass ratio of the TEAC to DMSO was 5 ∶16,extrusion temperature was 140 ℃,crewspeed was 60 r/min and glycerol triacetate content was 5%,where the tensile strength and flexural strength of bio-based plastics reached 16.33 MPa and 34.71 MPa,respectively. The morphology and structure of the resulting product were investigated by scanning electronmicroscopy(SEM),Fourier transform infrared(FT-IR) spectroscopy,X-ray diffractometry(XRD),thermogravimetric analysis(TGA) and differential thermal analysis(DTA). The results from the XRD and FT-IR revealed that the crystal structure of wood flour was destroyed due to the disruption of hydrogen bonds between cellulose chains during the process of modification and extrusion. The decreased Tg(glass transition temperature) of the modified product and extruded product indicated that the thermal stability of the modified product and extruded product decreased compared with rawwood material. No obvious crack was found on the surface of the extruded product from the SEMimages,which would contribute to the improvement of the mechanical property of the extruded product.
【Fund】： 国家林业公益性行业科研专项(201204803);; 江苏高校优势学科建设工程资助项目(PAPD)
【CateGory Index】： TQ321
【CateGory Index】： TQ321