淀粉胶粘剂接枝参数的影响因素及对其压缩剪切强度的影响

以过硫酸铵(简称APS)为引发剂,以醋酸乙烯酯为接枝单体,在水相介质中制备了蜡质玉米淀粉胶粘剂。研究了APS的添加量、接枝温度、pH、接枝共聚时间、单体滴加速度、单体与淀粉的质量比、糊化热处理程度等因素对接枝共聚反应的影响,并研究了接枝参数与胶粘剂压缩剪切强度之间的关系。结果表明:当APS的添加质量为淀粉干基质量的1.16%、接枝温度为70℃、接枝共聚时间为3.5 h、滴加速度为0.105 8 mL/(kg.s)、单体与淀粉的质量比6∶5、糊化条件85℃、30 min时,接枝百分率最高(50.83%);接枝百分率和支链相对分子质量均对淀粉胶粘剂的压缩剪切强度有一定的影响,且接枝百分率对蜡质玉米淀粉胶粘剂压缩剪切强度的影响比支链淀粉相对分子质量对蜡质玉米淀粉胶粘剂压缩剪切强度的影响大。

Research on Influencing Factors of the Graft Parameters of the Starch-Based Wood Adhesive and the Relation between Grafting Parameters with Bonding Strength

The waxy corn starch-based wood adhesive was prepared in aqueous medium with the APS as the initiator,the vinyl acetate as the monomer.The effects of the adding amount of APS,grafting reaction temperature,pH,grafting reaction time、dripping time of monomer,the mass radio of monomer and starch,the degree of heat treatment temperature on the graft polymerization was studied.And the optimum conditions were acquired and listed as follows: an APS quantity of 1.16% of dry starch weight,a reacting temperature of 70 ℃,an reacting time of 3.5 h,a monomer’s adding rate of 0.1058 mL/(kg·s),a mass radio between monomer with starch of 6:5 and the heat treat conditions of 85 ℃30 min,the graft radio is largest up to 50.83%.The percent grafting and the average molecular weight of branched chain both have an good effect on the bonding strength,besides the percent grafting has a greater effect on the bonding strength than the average molecular weight of branched chain’s.