Oligomeric Antiplasticization of Poly(methyl methacrylate) with Long- Chain Chloroparaffins

PJ Yue and JH Mangalara and M Branham-Ferrari and DS Simmons, ACS APPLIED POLYMER MATERIALS, 7, 9503-9516 (2025).

DOI: 10.1021/acsapm.4c03751

Small-molecule diluents are an essential and long-standing tool in the improvement of polymer properties in applications ranging from coatings to structural plastics. In recent years, however, concerns regarding the potential environmental and health risks associated with leaching of small-molecule additives have driven an increasing need to scale back or eliminate diluents' use in a range of polymer applications. This poses a significant threat to multiple polymer industries, as in many cases, equally effective (and cost-effective) means of achieving necessary polymer properties are lacking. Here, we demonstrate a pathway to resolution of this challenge via use of oligomeric diluents that innately exhibit reduced leaching risk due to their larger molecular size and thus reduced matrix mobility, vapor pressure, and environmental solubility as compared to similar small molecules. Via combination of course-grained molecular simulations, atomistic molecular simulations, and experiments, we identify long-chain chloroparaffins as an excellent class of antiplasticizer for poly(methyl methacrylate) (PMMA) and likely for other carbonyl-containing polymers. We report enhancements in the glassy modulus approaching 50%, combined with reductions in glass transition temperature T g. Our results indicate that introduction of oligomeric additives exhibiting strong interactions with the host polymer, but possessing high flexibility and small segmental size relative to the host polymer, may offer a general pathway to leaching- resistant antiplasticization.

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