多重受热历史对PLA/MWCNTs复合材料结晶和熔融行为的影响  

Effect of multi-thermal history on crystallization and melting behavior of PLA/MWCNTs composites

作　　者：胡静雯[1] 卢秀萍[1] 石坚[1,2] 李红月[1] 

机构地区：[1]天津科技大学化工与材料学院,天津300457 [2]天津金发新材料有限公司,天津300308

出　　处：《材料科学与工艺》2016年第2期47-52,共6页Materials Science and Technology

基　　金：国家自然科学基金资助项目(20976131)

摘　　要：为改善聚乳酸(PLA)的结晶性能,分别以PLA和表面包覆纳米SiO_2并接枝硅烷偶联剂的多壁碳纳米管(MWCNTs)为基体和改性剂,经溶液共混法制备PLA/MWCNTs复合材料.分别利用POM和DSC研究复合材料等温结晶、非等温结晶和冷结晶的球晶形态、结晶和熔融行为.研究结果表明:PLA/MWCNTs复合材料结晶和熔融行为强烈依赖于受热历史和改性MWCNTs含量;PLA/MWCNTs复合材料冷结晶时结晶度最高,球晶尺寸最小且熔点最低;1℃/min降温结晶时球晶尺寸最大,且熔点最高;降温速率越快,复合材料的起始结晶温度、结晶焓和结晶度越低.改性MWCNTs可作为PLA的异相成核剂,改善复合材料的结晶、熔融行为和球晶尺寸,其最佳用量为0.3%.In order to improve the crystallization properties of polylactic acid（ PLA）,PLA and MWCNTs coated by nano-SiO_2 and grafted with silane couple agent of KH- 550 were selected as matrix and modifier respectively to prepare PLA/MWCNTs composites via solution blending. POM and DSC were used to investigate the spherulitic morphology of the isothermal crystallization,non-isothermal crystallization and cold crystallization,crystallization and melting behaviors of the composites respectively. The results indicate that the crystallization and melting behaviors of the composites strongly depend on the thermal history（ crystallization condition） and the content of modified MWCNTs. The highest crystallinity,the smallest spherulite size and the lowest melting temperature of the composites can be obtained for the PLA/MWCNTs composite under cold crystallization. The composites have the largest spherulite size and the highest melting temperature under non-isothermal crystallization with a cooling rate of 1 ℃/min. The faster the cooling rate,the lower the initial crystallization temperature and crystallization enthalpy and crystallinity of the composites under non-isothermal crystallization. The modified MWCNTs can act a heterogeneous nucleation agent to significantly affect the crystallization property,melting behavior and spherulite size. The optimum dosage of modified MWCNTs is 0.3wt% in this work.

关 键 词：受热历史 聚乳酸 多壁碳纳米管 复合材料 结晶 熔融 

分 类 号：TB324[一般工业技术—材料科学与工程]