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Abstract
For the past few decades, researchers have been intrigued by glassy polymers, which have applications ranging from gas separations to corrosion protection to drug delivery systems. The techniques employed to examine the sorption and diffusion of small molecules in glassy polymers are the subject of this review. Diffusion models in glassy polymers are regulated by Fickian and non-Fickian diffusion, with non-Fickian diffusion being more prevalent. The characteristics of glassy polymers are determined by sorption isotherms, and different models have been proposed in the literature to explain sorption in glassy polymers over the last few years. This review also includes the applications of glassy polymers. Despite having many applications, current researchers still have difficulty in implementing coating challenges due to issues such as physical ageing, brittleness, etc., which are briefly discussed in the review.
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La Scala JJ, Yandek G, Lamb J, Paquette CM, Eck WS, Adams V, Lastovickova D, Sadler JM. The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system. HIGH PERFORM POLYM 2020. [DOI: 10.1177/0954008319899141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline diamines. Various anilines were condensed with paraformaldehyde under acidic conditions to yield dianilines. These dianilines and diamines were reacted with nadic anhydride and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in methanol to form the polyamic acid oligomers and heated at elevated temperature to form polyimide oligomers. It was found that the molecular weight of the oligomers derived from MDA alternatives was generally lower than that of MDA oligomers resulting in lower glass transition temperatures ( T gs) and degradation temperatures. Additionally, methoxy substituents further reduce the T g of the polymers versus methyl substituents and reduce the thermal stability of the resin. Methyl-substituted alternatives produced polyimides with similar T gs and degradation temperatures. The toxicity of the MDA alternatives was examined. Although a few were identified with reduced toxicities, the alternatives with properties similar to that of MDA also had high toxicities.
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Affiliation(s)
- John J La Scala
- CCDC Army Research Laboratory, FCDD-RLW-M, Aberdeen Proving Ground, MD, USA
| | - Greg Yandek
- Air Force Research Laboratory, Edwards AFB, CA, USA
| | - Jason Lamb
- Air Force Research Laboratory, Edwards AFB, CA, USA
| | | | - William S Eck
- Army Public Health Center, Aberdeen Proving Ground, MD, USA
| | - Valerie Adams
- Army Public Health Center, Aberdeen Proving Ground, MD, USA
| | | | - Joshua M Sadler
- CCDC Army Research Laboratory, FCDD-RLW-M, Aberdeen Proving Ground, MD, USA
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Vidil T, Cloître M, Tournilhac F. Control of Gelation and Network Properties of Cationically Copolymerized Mono- and Diglycidyl Ethers. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas Vidil
- Matière Molle et Chimie, UMR 7167 CNRS ESPCI Paris, PSL Research University, 10 rue Vauquelin 75005 Paris, France
| | - Michel Cloître
- Matière Molle et Chimie, UMR 7167 CNRS ESPCI Paris, PSL Research University, 10 rue Vauquelin 75005 Paris, France
| | - Francois Tournilhac
- Matière Molle et Chimie, UMR 7167 CNRS ESPCI Paris, PSL Research University, 10 rue Vauquelin 75005 Paris, France
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