SusChEM: Pro-Active Networks from Degradable Acetals (PANDAs) via Thiol-ene Photopolymerization

SusChEM：通过硫醇烯光聚合从可降解乙缩醛 (PANDA) 形成主动网络

• 批准号: 1710589
• 负责人: Derek Patton
• 金额: $ 42万
• 依托单位: University of Southern Mississippi
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710589&HistoricalAwards=false
• 关键词: SusChEM; Pro; Active; Networks; Degradable

Synthetic polymers are typically resistant to degradation and far outlive the useful lifetime of the use for which they are designed - a problem that results in the accumulation of plastics in landfills and oceans. Even upon degradation, the byproducts of plastics are sometimes toxic and serve no useful or active purpose in the environment. The Macromolecular, Supramolecular, and Nanochemistry (MSN) program of NSF Chemistry Division supports the efforts of Professors Patton and Mavrodi at the University of Southern Mississippi to advance the design of degradable polymers. Essential oil derivatives are used as primary building blocks of the polymers. The materials are designed to undergo complete degradation under mild conditions resulting in regeneration of essential oils. Stemming from the broad-spectrum antimicrobial and antifungal activity observed for many essential oil constituents, these degradable materials are potentially useful for a range of pharmaceutical, biomedical, and agricultural applications. The researchers have established active outreach programs to local K-12 schools including the ?What is a Polymer? program (impacting 500 students annually) and the ?Discover Nature? summer science camp. A new outreach initiative and collaboration with the local 3D (Dynamic Dyslexia Design) School is initiated. ?Science Nights @ 3D? engage dyslexic students (and their families) with hands-on activities that require visual, kinesthetic, and auditory processing while introducing fundamental, grade appropriate science and math concepts.The overarching goal of this project is the design, synthesis, and characterization of degradable polymer thermosets called "pro-active networks from degradable acetals (PANDAs)" via thiol-ene photopolymerization. The approach is rooted in the design of multifunctional acyclic and cyclic acetal monomers derived from essential oil precursors that enable control over network chemistry and network structure for tunable degradation profiles. PANDAs covalently incorporate aldehydes (e.g., vanillin, anisaldehyde, citronellal) and phenolic compounds (carvacrol, thymol) derived from essential oils directly into the polymer network via an acetal linkage - either as pendant groups (cyclic acetal) or as an integral part of the polymer backbone (acyclic acetal). Exposure to conditions conducive to acetal degradation (e.g., change in humidity/pH) regenerates the essential oil building blocks. Degradation profiles are determined to ascertain the erosion mechanism (surface vs. bulk) and aldehyde/phenol release kinetics, and to correlate degradation/release profiles with chemical and physical properties of the polymer network (e.g., hydrophobicity and crosslink density). The project actively trains a diverse group of graduate and undergraduate students in an interdisciplinary research environment and engages local K-12 schools, in outreach. This includes a collaboration with the local Dynamic Dyslexia Design (3D) School.

合成聚合物通常不易降解，寿命远远超过其设计的使用寿命——这一问题导致塑料在垃圾填埋场和海洋中堆积。即使在降解后，塑料的副产品有时也是有毒的，对环境没有任何有用或积极的作用。美国国家科学基金会化学部的大分子、超分子和纳米化学（MSN）项目支持南密西西比大学Patton和Mavrodi教授推进可降解聚合物设计的努力。精油衍生物被用作聚合物的主要组成部分。这些材料被设计成在温和的条件下完全降解，从而使精油再生。由于在许多精油成分中观察到广谱抗菌和抗真菌活性，这些可降解材料在一系列制药，生物医学和农业应用中具有潜在的用途。研究人员在当地的K-12学校建立了积极的外展项目，包括？什么是聚合物？项目（每年影响500名学生）和？发现大自然吗?暑期科学营。与当地3D（动态阅读障碍设计）学校开展了一项新的外展倡议和合作。？科学之夜@ 3D？让有阅读困难的学生（和他们的家庭）在介绍基本的、适合年级的科学和数学概念的同时，参与需要视觉、动觉和听觉处理的实践活动。该项目的总体目标是通过巯基光聚合设计、合成和表征可降解聚合物热固性，称为“可降解缩醛（PANDAs）的主动网络”。该方法植根于从精油前体衍生的多功能无环和环缩醛单体的设计，这些单体能够控制网络化学和网络结构，以实现可调的降解谱。PANDAs将从精油中提取的醛（如香兰素、茴香醛、香茅醛）和酚类化合物（香芹酚、百里香酚）通过缩醛键直接结合到聚合物网络中——要么作为悬垂基团（环缩醛），要么作为聚合物主链的组成部分（无环缩醛）。暴露于有利于缩醛降解的条件下（例如，湿度/pH值的变化）可再生精油构建块。测定降解谱以确定侵蚀机制（表面与整体）和醛/酚释放动力学，并将降解/释放谱与聚合物网络的化学和物理性质（例如疏水性和交联密度）联系起来。该项目在跨学科的研究环境中积极培养多样化的研究生和本科生群体，并与当地K-12学校进行外展。这包括与当地动态阅读障碍设计（3D）学校的合作。

项目成果

Command-destruct thermosets via photoinduced thiol-catalyzed β-scission of acyclic benzylidene acetals

通过光诱导硫醇催化无环亚苄基乙缩醛的 β 断裂命令破坏热固性材料

• DOI: 10.1039/d0py01006e
• 发表时间: 2020
• 期刊: Polymer Chemistry
• 影响因子: 4.6
• 作者: Walker, William D.;Sandoz, Michael J.;Roland, Samuel;Buster, Tony M.;Newman, John K.;Patton, Derek L.
• 通讯作者: Patton, Derek L.