立构嵌段聚乳酸的合成及结构性能表征  

Preparation and Characteristics of Stereo-block PLA Through Sequent Ring-Opening Polymerization

作　　者：王睿[1] 朱志国[1] 戈欢 马萌[1] 王锐[1] 

机构地区：[1]北京服装学院材料科学与工程学院,北京100029

出　　处：《塑料》2016年第3期68-72,共5页Plastics

摘　　要：文章以左旋丙交酯（L—LA）为单体，以辛酸亚锡和月桂醇分别作为催化剂和引发剂，在二甲苯中开环聚合得到3种不同分子量的左旋聚乳酸（PLLA），然后以其作为大分子引发剂，在基本同样的条件下，继续引发右旋丙交酯（D—LA）开环聚合，期望获得PLLA和PDLA的立构嵌段共聚物（sb—PLA）。采用核磁共振谱、X射线衍射、红外光谱和凝胶渗透色谱等对产物的结构进行了表征。结果表明：产物为单一立构嵌段聚乳酸。结合差示扫描量热仪（DSC）、热失重（TGA）和偏光显微镜（POM）对产物热性能和结晶性能进行了研究。与PLLA相比，sb-PLA的冷结晶温度（Tcc）下降25oC，但熔点（Tm）却高出50～60cc，这主要归因于PLLA—b—PDLA分子链中形成了更高紧密堆积的立构复合晶体，立体复合聚乳酸的结晶能力要明显强于PLLA或者PDLA。Poly（L-lactide） （PLLA） with varied molecular weights were synthesized by using ring-opening polymerization （ROP） of L-lactide （L-LA） , in which lauryl alcohol and Sn（Oct） 2 as initiator and catalyst, respectively. Subsequently, the PLLA were used as macroinitiator to initiate the ROP of D-lactide（D-LA）. The stereoblock PLA （sb-PLA） were expected to form through sequent ROP of L-LA and D-LA. A series of characterization methods, namely nuclear magnetic resonance spectroscopy （NMR）, X-ray diffraction （XRD）, IR spectrum and gel permeation chromatography （GPC） were applied to investigate the structure and properties of the products. Completely stereoblock-PLA （sb-PLA） were verified. Results from differential scanning calorimetry（DSC） indicated that the melting temperature （ Tm ） of sb-PLA was above 200 ~C , much higher than that of pure PLLA. In addition, the cooling crystallization temperature（ Tcc ） of sb-PLA decreased by 25 ~C compared with the PLLA. It was largely attributed to the closely packed stereocomplex crystals, which possess higher crystallization rate than homo crystals of PLLA or PDLA.

关 键 词：聚乳酸 开环聚合 立构嵌段 热性能 结晶性能 

分 类 号：Q946.816[生物学—植物学]