聚碳酸亚丙酯/木质素熔融共混改性研究

Modification of Poly (Propylene Carbonate) by Blending Lignin

关键词:  木质素  聚碳酸亚丙酯  降解  改性  熔融共混

Key Words:lignin  poly (propylene carbonate)  degradation  modification  melt blending

摘要:采用熔融共混法将木质素与聚碳酸亚丙酯(PPC)共混改性,研究木质素的种类和掺加比例对PPC/木质素共混物相容性、玻璃化转变温度(Tg)、热失重温度、力学性能及降解性能的影响,进一步探讨木质素改性PPC的作用机理。结果表明,当碱木质素(AL)含量10%时,PPC/AL共混物Tg为30.9℃,较PPC的提高8.9℃,热失重温度(T-5%、T-50%和Tmax)基本不变；当AL含量40%时,PPC/AL共混物拉伸强度为13.44 MPa,较PPC的提高213%,断裂伸长率为115%,较PPC的降低86%,第12天降解率可达44%。当木质素磺酸钙(CLS)含量20%时,PPC/CLS共混物Tg、T-5%、T-50%和Tmax分别为32.1、196.5、293.8和292.5℃,较PPC的分别提高10.1、3.0、56.7和60.5℃；当CLS含量为40%时,拉伸强度可达10.06 MPa,较PPC的提高134%,断裂伸长率为397%,较PPC的降低52%,第12天降解率可达38%。酯化反应和氢键作用等可能是木质素提高PPC性能的主要因素。

Abstract:Biodegradable blends of poly (propylene carbonate) (PPC) were prepared by melt blending with lignin, the effect of type of lignin and mixing ratio of lignin on the miscibility, glass transition temperature(Tg), weight loss temperature, mechanical properties and degradation of PPC/Alkali Lignin(AL) as well as the mechanism of PCC modification with lignin were investigated. The results showed that the Tg of PPC/AL blend is 30.9℃ that increases by 8.9℃ compared with PPC and T-5%, T-50% and Tmax of PCC/AL are essentially unchanged; the tensile strength increases from 4.30 MPa of PPC to 13.44 MPa of PPC/AL blends and the elongation at break decreases from 830% of PPC to 115% of PPC/AL when AL percentage is 40%, its degradation rate in the 12th day can reach 44%; the Tg, T-5%, T-50% and Tmax of PPC/Calcium Lignosulfonate (CLS) blend are respectively up to 32.1, 196.5, 293.8 and 292.5℃, which increase by 10.1, 3.0, 56.7 and 60.5℃ correspondingly. When the CLS percentage is 20%, the tensile strength reaches to 10.06 MPa that is increased by 134% compare to PCC and the elongation at break is 397% that is less than PPC by 52%, and the degradation rate in the 12th day is up to 38%. Esterification and hydrogen bond are the mainly reaction between lignin and PPC.