柠檬酸对(3-巯基丙基)三甲氧基硅烷改性木聚糖/聚乙烯醇复合膜性能的影响

Effect of citric acid on properties of(3-mercaptopropyl)trimethoxysilane modified xylan/polyvinyl alcohol composite film

为了改善木聚糖基薄膜易吸湿和力学强度低的缺陷,针对性提出柠檬酸(CA)与硅烷改性木聚糖(MSMX)协同作用的制备工艺。采用(3-巯基丙基)三甲氧基硅烷(MPTMS)对木聚糖进行疏水改性,以柠檬酸作为交联剂或增塑剂,通过流延法制备硅烷改性木聚糖(MSMX)/聚乙烯醇(PVA)/柠檬酸(CA)复合膜,并研究CA含量对复合膜结构及包装性能的影响。结果表明:随着CA含量的增加,MSMX/PVA/CA薄膜的交联程度增强,内部结构变得更加致密,从而导致其力学性能和水蒸气阻隔性能显著增强,同时伴随着亲水基团的减少,复合膜的疏水性提高。当CA添加量为20%(质量分数)时,MSMX/PVA/CA薄膜的拉伸强度为41.8 MPa,水接触角为82°,水蒸气透过系数可达2.79×10^(-13) g·cm·cm^(-2)·s^(-1)·Pa^(-1),比不加CA降低了37.79%。CA的添加改善木聚糖基复合膜的阻湿性能和力学强度,使其在食品和药品包装领域具有潜在应用。

In order to improved the defects of xylan-based films such as strong hygroscopicity and low mechanical strength,a collaborative modification protocol of citric acid(CA)and MPTMS-modified xylan(MSMX)was proposed.Xylan from sugarcane bagasse was firstly modified by(3-mercaptopropyl)trimethoxysilane(MPTMS),and then citric acid was used as crosslinking agent or plasticizer.The MSMX/PVA/CA films were prepared by casting method and the effects of citric acid content on the structure and packaging performance of the composite film were studied.The results show that with the increase of CA content,the cross-linking degree of MSMX/PVA/CA films increases and the internal structure becomes more dense,which lead to the significant enhancement of mechanical properties and water vapor barrier performance.Meanwhile,the hydrophobicity of the MSMX/PVA/CA films is improved with the decrease of hydrophilice groups.When CA content is 20%(mass fraction),the tensile strength of MSMX/PVA/CA film is 41.8 MPa,water contact angle is 82°,and the water vapor transmittance reaches 2.79×10^(-13 )g·cm·cm^(-2)·s^(-1)·Pa^(-1),which is 37.79% lower than that of film without CA.The addition of CA improves the moisture barrier properties and mechanical strength of xylan composite films,which makes it have a potential application in the field of food and drug packaging.