甲醛交联碱木质素-聚乙烯醇薄膜的透光性和透气性  

Light transmittance and gas permeability of alkaline lignin-poly vinyl alcohol film with formaldehyde crosslinker

作　　者：苏玲[1] 方桂珍[1] 

机构地区：[1]东北林业大学生物质材料科学与技术教育部重点试验室,哈尔滨150040

出　　处：《农业工程学报》2014年第4期239-246,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家林业局行业公益项目(20120480306);"十二五"国家科技计划课题(2012BAD24B04)

摘　　要：为了提高工业碱木质素的利用价值,扩大碱木质素的应用范围,以工业碱木质素和聚乙烯醇为原料,以甲醛为交联剂,利用流延法制备了碱木质素-聚乙烯醇交联反应膜。通过单因素实验探索了碱木质素加入量、甲醛加入量、溶液pH值对碱木质素-聚乙烯醇(PVA,poly vinyl alcohol)反应膜透光性和透气性的影响。采用紫外可见分光光度计分析了薄膜的光学性能,压差法测定薄膜的透气性。采用SEM(scanning electron microscopy)和FTIR(Fourier transform infrared spectroscopy)方法分析反应膜的表面形貌和化学结构,利用静态接触角测量仪测定薄膜的接触角。结果表明:碱木质素加入后,在紫外光区200～400 nm薄膜的透过率为零,对紫外线全吸收,在可见光区400～800 nm薄膜透过率降低,当碱木质素与PVA质量比为1:4时,在600 nm处薄膜的透过率为16.12%;随着甲醛加入量的提高,薄膜可见光区的透光率逐渐增大;随着pH值增大,木质素逐渐溶解,pH值为9时,薄膜600 nm处薄膜透过率为20.85%。与纯PVA薄膜相比较,碱木质素加入后薄膜二氧化碳和氧气的透气性都减小;经甲醛交联后,薄膜的氧气和二氧化碳的透过量都增大;pH值由小到大变化时,碱木质素-聚乙烯醇反应薄膜对二氧化碳和氧气的透气量先增大后减小。FT-IR表征说明碱木质素-聚乙烯醇薄膜结构中有醚键生成,碱木质素和PVA发生了交联反应;电镜图片显示碱木质素-聚乙烯醇反应薄膜表面较光滑;接触角分析说明碱木质素的加入增大了薄膜与水的接触角,薄膜表面亲水性降低,并且交联反应薄膜的接触角大于共混薄膜的接触角,交联提高了薄膜的耐水性。与戊二醛相比甲醛做交联剂时碱木质素和PVA之间的交联反应程度更大,交联薄膜在可见光区的透光性更大。薄膜对紫外线吸收主要是受碱木质素的影响。碱木质素-聚乙烯醇反应膜可作为良好的紫外吸收材料,应�In order to improve the utilization value of an industrial alkaline lignin and expand the application range of alkali lignin, with alkaline lignin and poly （vinyl alcohol） as the primary materials, and formaldehyde as a crosslinker, alkaline lignin/poly （vinyl alcohol） cross-linked film was prepared by casting. The effects of the dosage of alkaline lignin, formaldehyde, and the pH values on the light transmittance and gas permeability of the films were investigated one at a time for different variables. The light transmittance and gas permeability properties were measured using a double-beam UV-Vis spectrophotometer and a VAC-VBS pressure difference gas permeameter respectively. The surface morphology and chemical structure of the films were characterized by SEM and FT-IR. The results were as follows. （1） Influence of different conditions on the optical properties of the films： Alkaline lignin had a great influence on the absorbance and transmittance of films. The UV absorbance of the reaction films was nearly 100% among 200-400nm and the transmittance decreased during 400-800nm in the visible area. When the mass ratio of the alkaline lignin and PVA was 1：4, the transmittance was 16.12% at 600nm. The more formaldehyde, the higher the transmittance of the reaction films in the visible area. Besides, when the pH value was 9, the film transmittance was better. （2） Influence of different conditions on the gas permeability properties of the films： Both the carbon dioxide and oxygen transmittances were reduced after adding alkaline lignin, but increased with the formaldehyde added and first increased then decreased with the pH value changing from 5 to 11. （3） FT-IR showed that the ether linkage was formed and the cross-linking reaction was occurring between the alkaline lignin and PVA. The surface of the reaction films was smooth. The water contact angle of the reaction film was bigger than the blend, although the water contact angle of the composites both increased with the alkaline lignin ad

关 键 词：薄膜 聚乙烯醇 甲醛 交联 透光性 透气性 碱木质素 

分 类 号：TQ437.2[化学工程] TQ337.1