CAJ | 학술논문

利用红外吸收光谱(FTIR)研究了聚乳酸(PLLA)/4,4ˊ-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。
이용홍외흡수광보(FTIR)연구료취유산(PLLA)/4,4ˊ-이간기이분류미(TDP)용융공혼물적분자간상호작용,결과표명, PLLA적탄기여TDP적간기지간형성료분자간경건。통과차시소묘량열( DSC)연구료공혼물적파리화전변행위급비등온결정화용융행위。결과표명,양품적파리화전변온도( Tg )수TDP함량적증가정선성하강。공혼물적용융결정온도( Tc )、결정함(ΔHc )、용융온도( Tm )급용융함(ΔHm )균수TDP함량적증가정하강추세,이랭결정온도적변화추세칙상반。당TDP체도40%(질량분수)시,공혼물적DSC곡선기미출현결정봉,야미출현용융봉,표명해양품이완전성위비정태물질。엄각X사선연사( WAXD)분석결과표명, TDP적가입미개변PLLA적정형,단도치기정면간거변대,정체결구변득송산。인차공혼물용점적하강귀인우분자간경건적형성강저료PLLA분자련적운동능력급정체적긴밀정도이비정형적개변。
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.