一缩二乙二醇二甲基丙烯酸酯接枝真丝的结构

通过电子扫描电镜 (SEM)、红外光谱 (IR)、双折射、X 射线衍射及氨基酸分析等手段 ,研究了真丝用一缩二乙二醇二甲基丙烯酸酯 (P 2 )接枝后其结构与接枝率之间的关系 .氨基酸分析结果表明P 2接枝主要在真丝大分子中酪氨酸、丝氨酸、组氨酸和精氨酸的NH2 、OH和—NH—活性基团上 .通过X 射线衍射分析 ,P 2接枝并不直接影响结晶区 ,但引起分子取向的下降 ,接枝后真丝双折射下降说明接枝后因大分子取向度下降 ,接枝真丝的红外光谱显示出真丝具有 β折迭结构和P 2高聚物的结构特征峰 ,从而说明P 2接枝在纤维的无定型区内部进行 .当接枝率大于 35 %时 ,纤维的表面覆盖了一层高聚物 (P 2 ) ,并且纤维的横截面表现出明显的分纤现象 ,接枝真丝的红外光谱表明了纤维与P 2重叠吸收峰 ,说明了P 2在丝纤维内部接枝聚合 .

THE STRUCTURE OF THE SILK FIBERS GRAFTED WITH DIETHYLENE GLYCOL DIMETHACRYLATE

The effect of diethylene glycol dimethacrylate graft treatment on the structural changes of the silk fibers was examined in relation to the graft yield on the basis of the results of scanning electron micrograph photographs(SEM),infrared spectroscopy(IR),birefringence(Δ n ),X\|ray diffraction and amino acid analysis.The diethylene glycol dimethacrylate grafted silk fibers with different amounts of graft yield showed a substantial decrease of the amino acid composition of Tyr.,His.,Ser.,Arg.The other amino acid residues remained essentially unchanged or showed only slight changes,so,the diethylene glycol dimethacrylate exhibited reactivity toward Tyr.,His.,Ser.,and Arg.of silk fibers.X\|ray diffraction patterns of silk fibers suggested that the diethylene glycol dimethacrylate grafting does not affect directly the crystalline regions,but causes a decrease of molecular orientation in the amorphous regions.Birefringence(Δ n ) of silk fibers decreased by grafting with the diethylene glycol dimethacrylate.When the graft yields are more than 35%,the surface of silk fibers showed the presence of several granules,consisting of the diethylene glycol dimethacrylate polymers,and the cross\|sectional area of silk fibers showed the appearance of separating fiber.The IR of the grafted silk fibers showed absorption bands at 1651?cm -1 (amideⅠ) and 1520?cm -1 (amideⅡ) assigned to the β structure of the silk fibroin and additional bands at 1732,1134 and 1041?cm -1 ,characteristic of the spectra of the diethylene glycol dimethacrylate polymer.Additionally,the IR of the grafted silk fibers showed overlapped absorption bands due to the molecular conformation of this fiber and the diethylene glycol dimethacrylate polymer,giving evidence that the the diethylene glycol dimethacrylate graft occurred inside the fiber matrix.Thus the theoretical basis is provided for the silk chemical finishes or modification.