改性剂对聚乙烯醇薄膜力学性能的影响

Effect of Modifier on Mechanical Properties of Polyvinyl Alcohol Film

聚乙烯醇(PVA)是一种性能优异的可降解包装材料,但是,其熔点与分解温度接近,在受热熔融时发生分解。改性剂能降低聚乙烯醇的熔点,延缓分解,改善PVA的热塑加工性能,但是,影响了PVA薄膜的力学性能。实验研究了增塑剂、交联剂、稳定剂等改性助剂对PVA薄膜力学性能的影响。结果表明,随着丙三醇的添加,PVA薄膜拉伸强度降低,断裂伸长率提高,当丙三醇含量增加至40%时,断裂伸长率为293.84%;当醇解度为92时,薄膜的拉伸强度为30.54 MPa;添加硼砂能提升薄膜的拉伸强度,降低薄膜的断裂伸长率;当添加1份的氯化钙热稳定剂时,减少了PVA薄膜在加工过程中的热分解,对薄膜力学性能提升幅度较大,拉伸强度和断裂伸长率分别达到27.89 MPa、250.36%。

Polyvinyl alcohol(PVA) was a kind of degradable packaging material with excellent performance,but its melting point was close to the decomposition temperature,and melting was often accompanied by decomposition.The modifier could reduce the melting point of PVA,delay the decomposition,improve the thermoplastic processing performance of PVA,but would affect the mechanical properties of PVA film.The effects of plasticizer,cross-linking agent and stabilizer on mechanical properties of PVA film were investigated in the paper.The results showed that when the addition of glycerol increased,the tensile strength of PVA film decreased and the elongation at break increased.When the content of glycerol increased to 40%,the elongation at break reached 293.84%.When the alcoholysis was 92,the tensile strength of the film was 30.54 MPa.Adding borax could improve the tensile strength of the film and reduce the elongation at break of the film.Adding one part of calcium chloride heat stabilizer could reduce the thermal decomposition of PVA film in the process of processing,and improve the mechanical properties of the film greatly,the tensile strength and elongation at break were 27.89MPaand 250.36%,respectively.