聚己内酯在有机/无机杂化体系中的受限结晶行为

通过Sol Gel技术合成了聚己内酯 (PCL) /二氧化硅 (SiO2 )杂化材料 ,并对杂化样品进行了DSC和WAXD测试 .实验结果表明杂化样品中PCL的结晶度随二氧化硅含量增加而减小 ,当样品中二氧化硅含量达到 60 %时 ,PCL为非晶态 ;含有PCL结晶的杂化样品中PCL熔融温度基本相同 ,但是比纯PCL的熔融温度低 .杂化样品中结晶PCL的结晶结构和微晶尺寸和纯PCL的一致 .这说明杂化材料中PCL的结晶行为和结晶度受到了限制 ,含PCL结晶的样品中PCL的结晶结构和微晶尺寸并没有受到影响 .

CONFINED CRYSTALLIZATION BEHAVIOR OF PCL IN ORGANIC-INORGANIC HYBRID SYSTEM

poly( ε caprolactone) (PCL) and silica (SiO-2) organic|inorganic hybrid materials have been synthesized by sol|gel approach and the crystalline behavior of PCL in the silica networks has been investigated by differential scanning calorimetry (DSC) and wide angle X|ray diffraction (WAXD).The degree of PCL crystallinity in the PCL/SiO-2 hybrid networks reduces with the increase of SiO-2 content.PCL is in an amorphous state when the concentration of PCL is lower than 40wt% in the hybrid materials.The melting points of PCL in the networks are lower than that of pure PCL,but they almost have a same value.WAXD results show that when the PCL weight percentage is higher than 40wt% in the hybrid samples,part of PCL can crysatllize and the PCL crystallites are almost in a same size.That means the crystalline movement of PCL molecular chains is strictly confined by the porous gel.The crystalline PCL in the hybrid samples is relatively free from the composition of the materials,because the crystallization temperature and melting point of PCL of the samples are almost equal,and the crystalline PCL of different samples has the same crystalline structure and the same crystallite sizes L 110 and L 200 ,that means the crystalline part of PCL in the hybrid samples is unperturbed and the porous silica gel gives enough space for PCL to crystallize into the same crystalline structure and the same size crystallites.