基于三环二萜类小分子取向诱导聚乳酸微纳纤维化的分子模拟与实验研究

Molecular simulation and experimental study on micro/nanofibrillation of PLA induced by tricyclic diterpenes

聚合松香是三环二萜类结构小分子松香的二聚物,属于绿色可再生且可降解的化工原料。以小量聚合松香对聚乳酸进行诱导成纤,在常规的熔纺设备上即可获得连续的微纳米聚乳酸纤维束。使用Materials Studio对聚合松香与聚乳酸的共混过程进行分子动力学模拟。通过分析Flory-Huggins相互作用参数及径向分布函数,发现聚乳酸和聚合松香的比例在70∶30~40∶60之间时,相容性最好。通过热重分析,确定了共混体系纺丝温度为190℃,旋转流变测试证明了在纺丝过程中,聚合松香刚性小分子能够渗透到聚乳酸分子链之间。通过差示扫描量热测试得到聚合松香含量为50%时,结晶度达到了75.3%。熔融纺丝试验及电镜测试验证了40%的聚合松香可以使聚乳酸形成微纳米纤维束最细可达400 nm。

Polymerized rosin is a dimer of small molecule rosin with tricyclic diterpenoid structure.It is a green,renewable and degradable chemical raw material.The continuous micro nano poly(lactic acid)fiber bundles can be obtained on the conventional melt spinning equipment by inducing the fiber formation of poly(lactic acid)with a small amount of polymerized rosin.Materials Studio was used to simulate the blending process of polymeric rosin and polylactic acid.Through the analysis of Flory-Huggins interaction parameters and radial distribution function,it was found that when the ratio of polylactic acid and polymeric rosin was between 70∶30~40∶60,the compatibility was the best.The spinning temperature of the blend system was determined to be 190℃by thermogravimetric analysis.The rotational rheological test showed that the rigid small molecules of polymeric rosin could penetrate into the molecular chain of polylactic acid during the spinning process.The crystallinity reached 75.3%when the content of polymerized rosin was 50%by differential scanning calorimetry.Melt spinning test and electron microscope test verified that 40%of polymerized rosin can form micro/nano fiber bundle of polylactic acid,and the smallest can reach 400 nm.