木材用淀粉胶粘剂的制备及工艺优化

Processing Technology of High Solid Content Starch-Based Wood Adhesive

DOI：10.3969/j.issn.1673-1689.2015.07.009

中文关键词: 关键字: 淀粉 高固含量 二元种子法 工艺优化 机理分析

英文关键词: starch, high solid content, two-seed process, optimization of preparation, mechanism analysis

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中文摘要:

采用二元种子法工艺制备高固含量木材用淀粉胶粘剂。首先，研究了盐酸浓度对高固含量淀粉胶粘剂的降粘效果，综合考虑降解对粘接性能的影响，选择盐酸浓度为1.0 mol/L。其次，采用二元种子聚合工艺进一步降低体系的粘度和改善胶粘剂性能，研究了第一/第二种子比例和第二种子添加时间对淀粉胶贮藏稳定性的影响。结果表明，第一/第二种子比例为8∶2，反应进行2.5 h后加入第二种子，制备的淀粉胶表观粘度最低，贮藏性能最好。最后，优化了引发剂APS的添加量和添加方式:APS的添加总量为淀粉干基的1%，反应起始阶段加入总量的70%，取出第二种子后加入总量的20%，剩余的APS在加入第二种子后加入，制备过程中反应平稳，回流较少。在上述优化工艺的基础上对淀粉胶的粒径分析表明，二元种子法工艺制备的淀粉胶具有二元粒径分布，不同大小的粒子可达到最密堆积状态，且小粒子表面吸附了更多的乳化剂抑制淀粉回生，显著改善了高固含量木材用淀粉胶粘剂的贮藏性能。

英文摘要:

The high solid content starch-based wood adhesive was prepared by two-seed process. Firstly，the concentration effect of hydrochloric acid on viscosity of the high solid content starch-based wood adhesive was studied. Considering the degradation effect on shear strength，1.0 mol/L of hydrochloric acid was used. Then，two seed polymerization process was applied to further lower the viscosity of the system and improve the adhesive properties. Effects of the first/second seed ratio and the adding time of the second seed on storage stability of the high solid content starch-based wood adhesive were studied. It was shown that the adhesive showed the lowest viscosity and the best storage property with the first/second seed ratio of 8∶2 and the second seed being added after reacting for 2.5 h. Finally，the preparation was stable and less reflux with the conditions of 1% of APS(starch dry basis)，addition of 70% of the total APS at the beginning of reaction，10% of the total APS after adding the second seed and the rest 20% after taking out the second seed. The starch-based adhesive prepared by two-seed process possessed bimodal particle size distribution. The particles with different sizes reached the closest packing condition and more amount of emulsifier could be adsorbed on the surface of the small particles to restrain the starch retrogradation，which greatly improved the storage property of the high solid content of starch-based wood adhesive.

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