Plasticizer effect on the melting and crystallization behavior of polyvinyl alcohol

摘要

The melting and crystallization behavior of polyvinyl alcohol (PVA) were wxamined as a function of plasticizer amount.The melting temperature (T_m) of PVA decreased with increasing the amount of glycerin.The effect of a plasticizer rapidly diminshed when the phase separation of glycerin in PVA occurred.In addition,the crystallization peak temperature (T_c) of a fully hydrolysed PVA was reduced,and the maximum crystallization rate (K_(max)) was retarded,and the crystallite size distribution (omega_(1/2)) was widened.However,the crystallization behavior (T_c,K_(max),omega_(1/2)) of a partially hydrolysed PVA could be disregarded compared with a fully hydrolysed PVA.The thermal history did not affect the crystallization behavior of a fully hydrolysed PVA,but largely affected that of a partially hydrolysed PVA.In a fully hydrolysed PVA/a partially hydrolysed PVA blend system,two T_m peaks appeared,and the concurrent crystallization occurred.