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通过熔融缩聚法制备出含有聚乳酸支链的纤维素接枝共聚物(OLA-g-C),并采用溶液共混法制备一系列聚乳酸(PLA)/OLA-g-C共混物以及对比样聚乳酸/微晶纤维素(MCC)共混物.扫描电镜(SEM)结果表明聚乳酸支链的存在可以提高纤维素在PLA基体中的分散性,抑制团聚现象的出现.在非等温结晶过程中,OLA-g-C和MCC的加入都可以促进PLA的结晶,但是OLA-g-C的促进效果优于MCC,这与OLA-g-C在基体中的分散性良好有关.在等温结晶过程中OLA-g-C可以同时提高PLA的结晶度以及结晶速率,但对其成核机理和生长方式无明显影响.偏光显微镜(POM)观察的结果进一步证明OLA-g-C可以作为成核剂,有效地缩短基体的结晶时间,提高PLA的结晶能力.但是,OLA-g-C的加入却降低了体系的拉伸黏度,这与体系的缠结作用有关.
A series of polylactic acid (PLA) / OLA-gC blends were prepared by melt copolycondensation and the polylactide-containing cellulose graft copolymer (OLA-gC) / Microcrystalline cellulose (MCC) blends.The scanning electron microscopy (SEM) results showed that the presence of polylactic acid branched chains could improve the dispersibility of cellulose in PLA matrix and inhibit the appearance of agglomeration.In the process of non-isothermal crystallization, OLA-gC and MCC can promote the crystallization of PLA, but the promotion effect of OLA-gC is better than that of MCC, which is related to the good dispersibility of OLA-gC in matrix.In the process of isothermal crystallization, OLA-gC can increase at the same time PLA crystallinity and crystallization rate, but no significant effect on the nucleation mechanism and growth mode.Polymorphism observation (POM) results further prove that OLA-gC can be used as a nucleating agent, effectively shorten the crystallization time of the matrix, improve the PLA However, the addition of OLA-gC reduced the tensile viscosity of the system, which is related to the entanglement of the system.