功能化氮化硼纳米片对左旋聚乳酸结晶行为的影响

Effect of Functionalized Boron Nitride Nanosheets on Crystallization Behavior of PLLA

将羟基官能化氮化硼纳米片(OH-BNNS)与左旋聚乳酸(PLLA)共混,制备PLLA/OH-BNNS纳米复合材料,由于PLLA中羰基和OH-BNNS中羟基存在氢键相互作用,OH-BNNS良好地分散于PLLA中。通过各种技术手段研究了OH-BNNS对PLLA的熔融结晶行为,等温结晶动力学,宏观晶体形态、晶体结构的影响。发现添加OH-BNNS能有效加速PLLA的结晶,提高成核密度,导致球晶尺寸变小,结晶度增加,冷却时结晶峰更加明显,二次升温过程中冷结晶行为减弱。低OH-BNNS负载量可以增加α-晶的相对含量,但由于PLLA和OH-BNNS间强的相互作用,在高OH-BNNS负载量下,有序度较低的α′-晶的相对含量增加。

In this work,hydroxyl-functionalized boron nitride nanosheet(OH-BNNS)was prepared and was blended with poly(L-lactide)(PLLA)to yield PLLA/OH-BNNS nanocomposites with excellent dispersion of OH-BNNS via the interaction of carbonyl in PLLA and hydroxyl in OH-BNNS.The effects of OH-BNNS on the crystallization and melting behaviors,isothermal crystallization kinetics,macroscopic crystal morphology and crystal structure of PLLA were studied by means of various techniques.It is found that OH-BNNS can effectively accelerate crystallization of PLLA and enhance the nucleation density,leading to a smaller spherulite size,increased crystallinity,more obvious crystallization peak upon cooling but weakened cold crystallization behavior upon heating.Low OH-BNNS loading can increase the relative content ofα-crystal,but the relative content of less perfectα′-crystal is increased at high OH-BNNS loading due to the strong interaction between PLLA and OH-BNNS.