Abstract: A method for producing and recycling a crosslinked photopolymer is disclosed. The method includes mixing reactive thiols, multifunctional alkenes, and a photoinitiator to create a homogeneous mixture that is crosslinked through exposure to light. The method also includes decrosslinking the crosslinked photopolymer through base-catalyzed thiol-disulfide exchange reactions by mixing the crosslinked photopolymer with a reactive thiol, a base catalyst, and a solvent to create a decrosslinked material including recycled thiol oligomers which are reactive. The method further includes removing the base catalyst and the solvent and recrosslinking the recycled thiol oligomers by mixing stoichiometric amounts of the recycled thiol oligomers and a reactive alkene such that a molar ratio between thiol end groups and ene end groups is maintained at 1:1. The method includes adding a photoinitiator and mixing to create a homogeneous mixture, and recrosslinking the homogeneous mixture through exposure to light.

Abstract: A method for characterizing a melting transition in a semicrystalline polymer is disclosed. The method includes incorporating a fluorophore into the semicrystalline polymer, changing a temperature of the semicrystalline polymer to vary across a range of temperatures comprising a plurality of temperatures, and capturing an emission spectrum of the incorporated fluorophore at each temperature of the plurality of temperatures. The method also includes integrating each emission spectrum to determine a temperature-dependent integrated fluorescence intensity for the semicrystalline polymer, numerically differentiating the temperature-dependent integrated fluorescence intensity, and characterizing the melting transition of the semicrystalline polymer by identifying a stepwise change in value of the differentiated intensity. The semicrystalline polymer may be a thermoplastic.

Abstract: Disclosed herein are methods for reprocessing polyurethane compositions such as polyurethane foams. The method comprises introducing a polyurethane composition into a compounding device, heating the polyurethane composition to an effective bond-exchange temperature, and compounding the polyurethane composition for an effective bond-exchange time.

Abstract: A method comprises providing a polymer. The polymer is heated to a first predetermined temperature so as to liquefy the polymer. The liquefied polymer is formed into a polymer fiber. The polymer fiber is cross-linked to form a cross-linked polymer fiber comprising a polymer network by at least one of cooling the polymer fiber to a second predetermined temperature lower than the first predetermined temperature or exposing the polymer fiber to a cross-linking stimulus, the cross-linked polymer fiber capable of being decross-linked by heating to a third predetermined temperature above a characteristic decross-linking temperature of the polymer.

Abstract: Reorganizable or reprocessable cross-linked polymer networks with alkoxyamine dynamic covalent bonds and methods for preparation.

Abstract: Reorganizable or reprocessable cross-linked polymer networks with alkoxyamine dynamic covalent bonds and methods for preparation.