巯基-烯乳液聚合制备反应性微交联生物基乳胶及其固化性能研究

As film-forming materials for coatings, bio-based polymers have received extensive attention in recent years. In the face of increasingly stringent environmental requirements, it is of great significance to develop waterborne bio-based film-forming materials that can replace solvent-based film-forming materials. The hydrophilic groups of waterborne film-forming materials will lead to the decline of some properties of the film, which can be solved by increasing its crosslinking degree or molecular weight. However, uncontrollable crosslinking and molecular weight increase will lead to poor storage stability and batch stability of waterborne film-forming materials, which is difficult to meet the requirements of future use of film-forming materials for waterborne coatings. This project is based on molecular structure design, using the alicyclic or aromatic bio-based polythiol and polyene as monomers, to prepare reactive micro-crosslinking latex with thiol group or ene group via non-stoichiometric thiol-ene polymerization at emulsion. The bio-based ring structure and thioether bond of polymers will form a soft and hard alternated structure. The goals of this project are to develop bio-based latex with controllable reactivity, crosslinking degree and molecular weight, establish a balance control method between crosslinking degree and molecular weight of reactive micro-crosslinking bio-based latex, reveal the influence of latex structure on curing performance of coatings, and explore the application of reactive micro-crosslinking bio-based latex in low temperature curable and UV curable waterborne industrial coatings.

生物基聚合物作为涂料用成膜物近年来得到了广泛的关注，面对日益严厉的环保要求，研发可替代溶剂型成膜物的水性生物基成膜物的意义重大。水性成膜物的亲水基团会导致涂膜的部分性能下降，可通过提高交联度或增大分子量来解决，但不可控的交联和分子量增大会导致水性成膜物的贮存稳定性和批次稳定性差，难以满足未来水性涂料用成膜物的使用要求。本项目拟从分子结构设计出发，采用脂环族或芳香族生物基多元硫醇与多元烯进行非计量的巯基-烯乳液聚合，制备表面具有巯基或碳碳双键的反应性微交联生物基乳胶，生物基环状结构与聚合物的硫醚键形成软硬相间的结构；研究多层次分子结构与综合性能的关系，发展反应性、交联度和分子量可控的生物基乳胶，建立反应性微交联生物基乳胶的交联度与分子量间的平衡控制方法，揭示乳胶结构对涂层固化性能的影响规律，探索反应性微交联生物基乳胶在低温固化和UV固化水性工业涂料中的应用。

水性成膜物的亲水基团会导致涂膜的部分性能下降，一般通过提高交联度或增大分子量来解决，但这两种方法都会导致水性成膜物生产过程不易控制，产品的贮存稳定性和批次稳定性差，难以满足未来水性涂料用成膜物的使用要求。本项目从分子结构设计出发，将微交联结构设计在乳胶粒中，采用脂环族或芳香族生物基多元硫醇与多元烯进行非计量的巯基-烯乳液聚合，制备了表面具有巯基或碳碳双键的反应性微交联生物基乳胶，生物基环状结构与聚合物的硫醚键形成软硬相间的结构，可赋予材料优良的韧性。.本项目先以市售多元烯和多元硫醇为原料，采用非等量投料，通过巯基-烯乳液聚合制备了表面具有巯基或碳碳双键的反应性微交联乳胶，建立了巯基-烯乳液聚合制备反应性微交联乳胶的模型，并研究了含巯基的微交联乳胶用作水性环氧固化剂的应用性能，以及含碳碳双键的微交联乳胶用作水性UV树脂的应用性能。在此基础上，以自制的生物基多元烯和多元硫醇为替代原料，制备生物基反应性微交联乳胶，并研究其作为水性硫醇型环氧固化剂和水性UV树脂的固化性能。项目在以下方面具有应用潜力：含巯基的微交联乳胶可用作特殊的水性环氧固化剂，因其固化所得涂膜同时具有高硬度和优异的柔韧和抗冲击性能，可用于水性环氧涂料的厚涂和较低温度下的固化，弥补现有水性胺类固化剂的不足、含巯基的微交联乳胶在水性UV涂料方面也有应用潜力，其可与现有常规树脂进行拼混，制备又强又韧的涂层。.本项目三年内共计发表论文13篇；申请4项发明专利，其中授权中国发明专利1项，美国发明专利1项，转让发明专利2项。有一些成果仍在整理中。.本项目为巯基-烯乳液聚合物及生物基原料在水性涂料领域的应用提供了实验基础和应用方向。