双重交联网络对聚乙烯醇泡沫性能的影响

Effect of double crosslinked networks on the properties of polyvinyl alcohol foams

以聚乙烯醇为原料,硼酸为交联剂,表面活性剂为致孔剂,通过机械搅拌和冷冻-解冻法制备了预交联软质聚乙烯醇泡沫。通过傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜(SEM)分析了泡沫的化学结构和微观结构,探究了硼酸含量对泡沫密度、吸水率、孔隙率和泡孔结构的影响;并通过γ射线辐照进行后交联提高聚乙烯醇泡沫的力学性能,研究了不同辐照剂量对聚乙烯醇泡沫压缩强度和拉伸强度的影响。结果表明:通过这种双交联方法制备出的PVA泡沫具有致密的泡孔结构和理想的表观密度,密度为0.096g/cm^(3),孔隙率为92.6%,吸水率可以达到自身的17.45倍。PVA泡沫的最佳辐照交联剂量为20~30kGy,压缩强度最高可达34.9kPa,比未交联的PVA泡沫提高了267.3%;拉伸强度达到150.6kPa,断裂伸长率可达126.95%,比未交联的PVA泡沫分别提高了96.1%和59.7%。

Pre-crosslinked flexible polyvinyl alcohol foams were prepared by mechanical mixing and freeze-thaw method using polyvinyl alcohol as raw material,boric acid as cross-linking agent and surfactant as porogenic agent.The chemical structure and microstructure of the foams were analyzed by Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM),and the effects of boric acid content on the density,water absorption,porosity,and pore structure of the foams were explored.The mechanical properties of polyvinyl alcohol foam were also improved by post-crosslinking throughγ-ray irradiation,and the effects of different irradiation doses on the compression strength and tensile strength of polyvinyl alcohol foams were investigated.The results showed that the PVA foams prepared by this double cross-linking method had a dense pore structure and a desirable apparent density,with a density of 0.096g/cm^(3),a porosity of 92.6%,and a water absorption capacity up to 17.45 times its own weight.The optimal amount of irradiation cross-linking agent for PVA foams was 20~30kGy,and the compression strength was up to 34.9kPa,which was increased by 267.3%compared to uncross-linked PVA foams.The tensile strength was up to 150.6kPa,and the elongation at break reached 126.95%,which was 96.1%and 59.7%higher than those of uncross-linked PVA foams,respectively.