复合单体TEGDMA/MAA接枝真丝纱线的工艺条件及试样的性能表征

为提高真丝接枝体系中的单体利用率,在真丝接枝体系中添加反应活性较高的三乙二醇二甲基丙烯酸酯(TEGD-MA)单体,与常用接枝单体甲基丙烯酰胺(MAA)复合,对真丝纱线进行化学接枝。经过单因素试验得出适宜的接枝工艺条件:TEGDMA/MAA复合单体用量为真丝纱线质量的70%,其中TEGDMA与MAA的质量比为1∶9,引发剂过硫酸钾(KPS)的浓度为5 mmol/L,pH≈2.5,反应温度80℃,反应时间60 min,吐温-80的质量浓度为0.2 g/L,浴比为1∶20。在此工艺条件下,TEGDMA/MAA复合接枝体系可获得约58%的接枝率,较相同接枝条件下的MAA接枝纱线提高了约16个百分点,同时其单体利用率达到83%,较MAA单体利用率提高了23个百分点。通过扫描电子显微镜观察发现接枝后的真丝纱线表面分布有接枝聚合物,接枝真丝纱线的红外光谱显示在1 700～1 800 cm-1处具有较宽的TEGDMA分子结构中CO双键的伸缩振动吸收峰,热重分析显示在500℃下接枝真丝纱线出现不同于MAA接枝纱线的失重速率峰,说明TEGDMA与MAA 2种单体分子均参与了接枝反应。

Technological Conditions for Grafting Silk Yarn with Compound Monomer TEGDMA/MAA and Property Characterization of the Grafted Sample

In order to increase the utilization rate of monomers,a high reactivity monomer triethylene glycol dimethacrylate(TEGDMA) was added to the grafting system of silk,and chemically grafted with silk yarns after compounding with the frequently used graft monomer acrylamide(MAA).The optimum technological condition for grafting was obtained through single-factor experiments: mass fraction of compound monomers TEGDMA/MAA to silk yarn 70%,mass ratio of TEGDMA and MAA 1 ∶9,initiator potassium persulfate(KPS) 5 mmol/L,pH≈2.5,reaction temperature 80 ℃,reaction time 60 min,mass concentration of Tween-80 0.2 g/L,and bath ratio 1 ∶20.Under this technological condition,grafting rate of the TEGDMA/MAA compound graft system reached about 58%,being about 16 percentage points higher than that of grafted yarns silk yarn grafted with MAA under the same technological condition.At the same time,the utilization rate of monomer reached 83%,being 23 percentage points higher than that of MAA.Scanning electron microscopic observation indicated that grafted polymers occurred at the surface of grafted silk yarns.Infrared spectra of the grafted silk yarns showed that there was a wide absorption peak characterizing stretching vibration of the C O double bond in molecular structure of TEGDMA in the range of 1 700～1 800 cm-1.Thermal gravimetric analysis demonstrated that weight loss rate of silk yarns grafted with the TEGDMA/MAA compound monomer at 500 ℃ had different peaks with that of silk yarns grafted with MAA.These results showed that monomers TEGDMA and MAA were both involved in grafting reaction.