聚L-乳酸/4,4＇-二羟基二苯硫醚共混物的分子间相互作用及结晶和熔融行为  

Intermolecular Interactions and Crystallization and Melting Behavior of Poly(L-lactic acid)/4,4'-Thiobis Phenol Blends

作　　者：司朋飞 罗发亮 海梅[1] 

机构地区：[1]宁夏大学化学化工学院 [2]能源化工重点实验室,银川750021

出　　处：《高等学校化学学报》2015年第1期188-194,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21264012,51063004)资助~~

摘　　要：利用红外吸收光谱(FTIR)研究了聚乳酸(PLLA)/4,4'-二羟基二苯硫醚(TDP)熔融共混物的分子间相互作用,结果表明,PLLA的羰基与TDP的羟基之间形成了分子间氢键.通过差示扫描量热(DSC)研究了共混物的玻璃化转变行为及非等温结晶和熔融行为.结果表明,样品的玻璃化转变温度(Tg)随TDP含量的增加呈线性下降.共混物的熔融结晶温度(Tc)、结晶焓(ΔHc)、熔融温度(Tm)及熔融焓(ΔHm)均随TDP含量的增加呈下降趋势,而冷结晶温度的变化趋势则相反.当TDP达到40%(质量分数)时,共混物的DSC曲线既未出现结晶峰,也未出现熔融峰,表明该样品已完全成为非晶态物质.广角X射线衍射(WAXD)分析结果表明,TDP的加入未改变PLLA的晶型,但导致其晶面间距变大,晶体结构变得松散.因此共混物熔点的下降归因于分子间氢键的形成降低了PLLA分子链的运动能力及晶体的紧密程度而非晶型的改变.The intermolecular interactions between poly （ L-lactic acid） （ PLLA） and 4,4ˊ-thiobis phenol （TDP） in their melt blending samples were studied by means of Fourier transform infrared（FTIR） spectro- meter. The results show that intermolecular hydrogen bonding forms between carbonyl groups of PLLA and hydroxyl groups of TDP. The glass transition behavior and non-isothermal crystallization, subsequent melting behavior of PLLA and PLLA/TDP blends were studied by differential scanning calorimeter（ DSC） . The results show that, glass transition temperatures （ Tg ） of the samples decrease linearly with TDP content. The melt crystallization temperatures（Tc）, heat of crystallization（ΔHc）, melting temperatures（Tm）, heat of fusion （ΔHm） all decrease with TDP content, while the cold-crystallization temperatures show reverse tendency. When TDP content reaches 40%（ mass fraction） in the sample, neither crystallization exothermic nor melting endothermic peaks appear in the DSC curve, implying that this sample is completely in amorphous state. Wide angle X-ray diffraction（ WAXD） analysis reveals that the addition of TDP does not modify the crystal structure of PLLA, but results in less compact crystal structure. Thus, the decrease of melting temperatures ought to attribute to the formation of intermolecular hydrogen bonding, which reduces mobility of PLLA chains and makes the resulting crystals less compact, rather than crystal modification.

关 键 词：聚L-乳酸 熔融共混 非等温结晶 4 4'-二羟基二苯硫醚 分子间相互作用 

分 类 号：O631.1[理学—高分子化学]