GOALI: New Generation of Acrylic Resins Produced through Spontaneous Thermal Polymerization

摘要：Masoud Soroush机构：Drexel大学提案编号：0651706标题：GOALI：通过自发热聚合生产的新一代丙烯酸树脂知识产权： 关于涂料挥发性有机物含量（VOC）的北美法规要求到2010年将允许的VOC从1990年的480 g/L减少到300 g/L以下。这些和类似的法规正在推动涂料中树脂基本性质的变化。固体含量为60 - 80重量%的低分子量、高度官能化的聚合物和低聚物溶液已经取代固体含量为30 - 40重量%的高分子量、非官能化的聚合物溶液作为涂料配方中的关键组分。生产低分子量聚合物溶液的一种有前途的方法是在高温下进行聚合。在这些高温下，在低温下不显著的副反应对聚合速率和分子结构形成具有非常强的影响。例如，丙烯酸烷基酯在高于140 ℃的温度下发生显著的、持续的、可再现的、自发的均聚和共聚，这是该团队在2002年首次报道的，几十年来，人们已经知道甲基丙烯酸酯和苯乙烯在高温下发生可再现的自发聚合。引发丙烯酸烷基酯自发热聚合反应的物种和引发机理尚不清楚。定量了解这些二次反应有助于设计更安全、更环保的聚合工艺，从而生产出新一代更高质量的溶剂型树脂。本项目首先设计了一种有效的实验方法，以确定（a）引发丙烯酸烷基酯自发聚合的痕量物质和（B）引发过程的机理。实验方法应保证引发剂种类和反应参数的可识别性。其次，在精心控制的条件下，按照实验方法进行了丙烯酸丁酯等丙烯酸烷基酯的高温自发聚合，并对聚合物结构进行了表征。第三，将这些结果与数学建模相结合，以细化机理途径并量化次级反应的动力学。第四，所开发的反应网络的参数的可识别性进行了调查，以确保足够的类型，数量和质量的测量。第五，构建了适用于丙烯酸烷基酯高温自由基聚合的通用模型，并结合实验室实验数据进行了检验。最后，通过使用开发的机理模型，反应器的设计配置，如半批，连续搅拌槽（CST），和混合（CST其次是半批）使用一种新的博弈论为基础的方法进行筛选，并计算出每个最佳设计配置的最佳配方。更广泛的影响：该项目的潜在影响是环境，经济和教育等。对二次反应的定量理解的改进导致以较低的运营成本生产新一代更高质量、更环保的溶剂型油漆和涂料。低分子量的聚合物和低聚物溶液即使在高重量百分比固体下也具有足够低的粘度，因此需要加入较少的有机溶剂。使用较少或不添加热引发剂（通常是树脂配方中最昂贵的组分）以及在较高温度下较短反应时间的适当性降低了操作成本。在最终产品中存在较少的来自热引发剂的残留基团（其不利地影响聚合物性能，例如耐紫外线辐射性），以及在分子性能的最佳控制中使用定量理解，提高了树脂质量。 包括杜邦在内的树脂和涂料行业主要受益于该项目的科学成果。该项目提供了一个博士学位。和两名本科生提供了一个宝贵的机会，以获得在工业环境中的研究经验。其结果在会议和期刊论文中向公众公布。

ABSTRACTPI: Masoud Soroush Institution: Drexel University Proposal Number: 0651706Title: GOALI: New Generation of Acrylic Resins Produced through Spontaneous Thermal PlymerizationIntellectual Merit: North American regulations on volatile organic content (VOC) of coatings require the reduction of allowable VOC's from 480 g/L of paint in 1990 to below 300 g/L by 2010. These and similar regulations are driving change in the basic nature of resin in coatings. Low molecular weight, highly functionalized polymer and oligomer solutions at 60 to 80 weight percent solids have replaced high molecular weight, non-functional polymer solutions at 30 to 40 weight percent solids as key components in coatings formulas. A promising method of producing low molecular-weight polymer solutions is to carry out the polymerization at high temperatures. At these high temperatures, secondary reactions, that are insignificant at low temperatures, have very strong effects on the polymerization rate and molecular structure formation. For example, alkyl acrylates undergo significant, sustained, reproducible, spontaneous homo- and co-polymerization at temperatures above 140.C, which was first reported by this team in 2002 methacrylates and styrene have been known for several decades to undergo reproducible spontaneous polymerization at high temperatures. The species that initiate the chain reactions in spontaneous thermal polymerization of alkyl acrylates and the initiation mechanism are yet unknown. A quantitative understanding of these secondary reactions allows one to design safer and environmentally-friendlier polymerization processes that produce a new generation of higher quality, solvent-borne resins.In this project, an effective experimental method is first designed to identify (a) the trace species that initiate the spontaneous polymerization of alkyl acrylates and (b) the mechanism of the initiation process. The experiment method should ensure the identifiability of the initiating species and the reaction parameters. Second, under carefully controlled conditions, high-temperature spontaneous polymerization of alkyl acrylates such as butyl acrylate is carried out according to the experiment method, and the polymer structure is characterized. Third, these results are combined with mathematical modeling to refine the mechanistic pathways and quantify the kinetics of the secondary reactions. Fourth, the identifiability of the parameters of the developed reaction network is investigated to ensure the sufficiency of the type, number and quality of measurements. Fifth, a general model applicable for high-temperature free radical polymerization of alkyl acrylates is constructed and tested against lab-scale experimental data. Finally, by using the developed mechanistic models, reactor design configurations such as semi-batch, continuous stirred tank (CST), and hybrid (CST followed by semi-batch) are screened using a novel game-theory-based method, and an optimal recipe for each optimal design configuration is calculated.Broader Impact: The potential impacts of the project are environmental, economic and educational, among others. The improved quantitative understanding of the secondary reactions leads to the production of a new generation of higher quality, environmentally-friendlier solvent borne paints and coatings at lower operating costs. Low molecular weight, polymer and oligomer solutions even at high weight percent solids have adequately low viscosity, thus requiring the addition of less organic solvents. The use of less or no added thermal initiators (normally the most expensive component of a resin formula) and the adequacy of shorter reaction times at higher temperatures lower the operating costs. The presence of less residual groups from thermal initiators (which adversely affect polymer properties such as resistance to UV radiation) in the final product and the use of the quantitative understanding in optimal control of molecular properties improve the resin quality. The resin and coating industries including DuPont benefit primarily from the scientific outcomes of this project. The project provides one Ph.D. and two undergraduate students with an invaluable opportunity to gain research experience in an industrial environment. Its results are released to the public at conferences and in journal papers.