魔芋粉-壳聚糖-聚乙烯醇共混胶黏剂的性能及其胶合机理

    Properties and bonding mechanism of konjak powder - chitosan - PVA blending adhesive

    • 摘要: 为了提高魔芋粉的利用价值,开发环境友好型木材胶黏剂,以魔芋葡甘聚糖、壳聚糖为胶黏剂主料,添加聚乙烯醇制备三元共混胶黏剂。通过差示扫描量热法(DSC),分析共混胶的热特性,确定了热压温度参数;采用正交试验法,探讨热压工艺参数对胶合板强度的影响,并进一步对比了二元共混胶和三元共混胶的强度;通过红外光谱(FTIR)和扫描电子显微镜(SEM)进行了微观结构分析。结果表明:在热压温度130℃,热压时间15 min,压力4 MPa,胶存放时间24 h的条件下,用该胶黏剂压制的胶合板,干湿状胶合强度最大;FTIR分析发现3种高分子之间存在着氢键等强烈的相互作用;SEM分析表明三元共混胶黏剂中存在网状结构,使胶合强度得到提高。研究结果为加速环保木材胶黏剂研发进程和完善加工工艺条件提供了科学依据。

       

      Abstract: In order to enhance utilization value of konjak powder and develop environment-friendly wood adhesive, konjac glucomannan and chitosan were blended as main raw bonding materials with adding polyvinyl alcohols (PVA). Thermal characteristics of the blending adhesive were analyzed to determine the hot-pressing temperature parameters by differential scanning calorimetry (DSC). Then the orthogonal experiment was used to investigate the effects of the process parameters on the bonding strength of plywood. The bonding strength of plywood using the konjak powder - chitosan blending adhesive was compared with PVA and without PVA, and the microstructure of the blending adhesives were also analyzed by infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Results showed that the plywood could reach the maximum value of bonding strength when the press temperature, press pressure, pressing time, and adhesive storage time was 130℃, 4 MPa, 15 min and 24 h, respectively. FTIR showed that there existed the strong interaction of hydrogen bond among the three kinds of molecular. SEM observations indicated that the blending adhesive with PVA had the net-like structure so as to increase its whole bonding strength. These results could provide scientific basis for accelerating process of the development of environmentally friendly wood adhesive and improving the processing condition.

       

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