聚己内酯/纳米二氧化硅复合体系环带球晶形貌及结晶行为研究

Study on Ring-banded Morphology and Crystallization Behaviors of PCL/Nanosilica Composite

采用溶液浇铸的方法制备了聚己内酯(PCL)/疏水性纳米二氧化硅(R974)复合体系薄膜,利用偏光显微镜、差示扫描量热仪、扫描电镜等研究了R974对PCL环带球晶形貌及结晶行为的影响,并从微观层次探讨了PCL/R974环带球晶可能的形成机理。结果表明,PCL/R974环带球晶是由扭转生长的片晶构成。R974的加入可诱导PCL环带球晶的形成,拓宽环带球晶形成温度。R974含量越高,PCL形成环带温度越低,环带周期越小,环带结构越规整。等温结晶时,R974加入并未改变PCL异相成核机理,但会影响其结晶动力学。当R974含量≤4%(wt)时,其异相成核作用占主导,促进了PCL结晶过程;当R974含量>4%(wt)时,其对于球晶生长的阻碍大于异相成核作用,最终抑制了PCL的结晶。

Poly （ε-caprolactone）（PCL）/hydrophobic nano-SiO2 （R974） composite were prepared via solution mixing. The Influence of R974 on the ring-banded morphology and crystallization behavior of PCL was investigated by differential scanning calorimetry （DSC）, optical microscopy （POM） and scanning electron microscopy（SEM）. The results indicate that the lamellar twisting mechanism can be demonstrated to explain the formation of ring-banded spherulites in PCL/R974 composite. Furthermore, the presence of R974 apparently widen the forming temperature range of ring-banded structure. The band periodicity is found to decline significantly with increasing R974 content. And the regularity of ring-band increases accordingly. R974 won＇t change the heterogeneous nucleation mechanism of PCL,but will influence its isothermal crystallization kinetic. For composite with low content （≤4% （wt）） of R974, the heterogeneous nucleation effect plays a major role in promoting the crystallization behavior. However, when the contents is higher than 4% （wt）, the crystallization is suppressed for dominated restriction in spherulite growth. Key words：Ring-banded spherulites; Poly （ε-caprolactone） ; Nanoparticles; Crystallization