一种环保型皮革涂饰材料

An eco-friendly leather coating material

制备蛋清（A）和明胶（B）的复合物，其产物可作为可生物降解的粘合剂。现将AB复合产物与戊二醛（C）交联形成复合物ABC。将制备好的ABC用FT-IR、TGA、CD光谱表征并检测其拉伸强度。在拉伸强度检测试验过程中，测试速度为5mm／min。结果表明：在40MPa下，体积比为AB：C=50：1，延长率为170％时，复合物ABC表现出的拉伸强度最佳。采用圆二色谱检测复合物结构，其光谱范围是185-250nm。检测结果表明：AB复合物中发现了螺旋结构，这说明存在肽键，而在ABC复合物中发现了无规卷曲，原本复合物AB的光谱在197nm处的负峰消失，说明螺旋结构转为了无规卷曲，戊二醛与AB复合物成功交联。采用红外光谱对复合物进行检测，结果发现：AB复合物红外光谱在1654cm^-1（酰胺I），1561cm^-1（酰胺Ⅱ），1244cm^-1（酰胺Ⅲ）处出现了蛋白质峰，而ABC复合物的红外光谱中酰胺Ⅲ缺失。这是由于戊二醛和氨基交联导致。对复合物进行热重分析，结果表明：AB复合物在235-400℃．失重就达到60％而ABC复合物在235-375℃的失重率仅有8％。对样品进行吸水性研究．结果表明：AB复合物在吸水不到1h就被溶解了．而ABC复合物在吸水24h后任然完好无损，1h后吸水率为173％。2h后吸水率为233％，3h后吸水率为245％，24h后吸水率为153％。ABC复合物在一张皮革表面进行标准涂饰来检测其剥离强度。结果表明在干燥条件下剥离强度为4．8N／mm，而在湿润条件下剥离强度为3．2N／mm。因此，ABC复合物有着优异的性能，可以用作皮革涂饰材料。

Hen egg white （A） and gelatin （ B ） composition that was used as a bio-degradable binder was prepared and the product is cross-linked with Glutaraldehyde （C）. The composition thus formed （ABc） was standardized with tensile strength and characterized with FT-IR, TGA, CD spectra. The tensile strength test was conducted on ABC composite at a speed of 5mm/min and it shows an optimum tensile strength of 40MPa with elongation （ 170% ） for AB and C at the ratio of 50 ： 1. The Circular Dichroism （CD） spectra was performed between 185 - 250nm and the AB composite shows an helical structure that confirms presence of peptide bond and for ABC composite an unordered random coil structure with negative peak at 197nm i. e. helical structure was converted into random coil that confirms the concept of cross linking of AB composite with Glutaraldehyde. The FT-IR spectra of AB composite shows protein peaks at 1 654cm^-1（Amide- Ⅰ ）, 1 561cm-l（Amide- Ⅰ ）, 1 244cm^-1（Amide-Ⅲ） whereas for ABC composite, the amide-Ⅲ band was absent, this is due to glutaraldehyde link with amide group. Thermal gravimetric analysis of AB composite shows 60% weight loss between 235℃to 400℃ and for ABC composite it was 8% between 235 - 375℃. Water absorption studies were conducted on samples and it was concluded that the AB composite was disintegrated within an hour whereas ABC composite （in the ratio AB ： C = 50 ： 1 ） was intact even after 24 hours and has water absorption capacity of 173%/mm^3, 233%/mm^3, 245%/mm^3, 153%/mm^3 after lhr, 2hr, 3hr and 24hrs respectively. The ABC composite is tested for peel strength by giving a coat on a standard leather surface and it was found to have 4. 8N/mm on dry condition and 3.2N/mm on wet condition. Therefore the proposed hen egg white-gelatin-glutaraldehyde （ABC） composite possesses excellent characteristics and can be used as a coating agent for Leather.