New Approach to Determine the Phase Transition Temperature,Cloud Point,of Thermoresponsive Polymers |
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| Authors: | Marli L. Tebaldi Luana A. Fiel Amilton M. Santos Silvia S. Guterres Adriana R. Pohlmann |
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| Affiliation: | 1. Universidade Federal de Itajubá , Campus Itabira (MG), Brazil;2. Departamento de Química Organica, Instituto de Química , Universidade Federal do Rio Grande do Sul , Porto Alegre , RS , Brazil;3. Programa de Pós-Gradua??o em Ciências Farmacêuticas, Faculdade de Farmácia , Universidade Federal do Rio Grande do Sul , Porto Alegre , RS , Brazil;4. Departamento de Engenharia Química , Escola de Engenharia de Lorena – Universidade de S?o Paulo , Lorena (SP) , Brazil;5. Departamento de Química Organica, Instituto de Química , Universidade Federal do Rio Grande do Sul , Porto Alegre , RS , Brazil;6. Programa de Pós-Gradua??o em Ciências Farmacêuticas, Faculdade de Farmácia , Universidade Federal do Rio Grande do Sul , Porto Alegre , RS , Brazil |
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| Abstract: | In this study, a novel method to determine the cloud point temperature variation in aqueous solutions of thermoresponsive homo- and copolymers was developed. Poly(N-vinylcaprolactam) (PVCL) and triblock copolymers of poly(t-butyl acrylate-co-acrylic acid)-b-poly(N-vinylcaprolactam)-b-(t-butyl acrylate-co-acrylic acid) (P[(tBA-co-AA)-b-PVCL-b-P(tBA-co-AA)] were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and used as models. The incorporation of AA units (hydrophilic segments) into the polymeric chain of PVCL influenced the phase transition, increasing the cloud point temperature of the final copolymer. The cloud point temperatures of the PVCL and the triblock copolymer P(tBA-co-AA)-b-PVCL-b-P(tBA-co-AA) were determined by measuring the transmittance of aqueous solutions of the polymers in a Turbiscan Lab instrument in the range of 29 to 40 C. This is the first study in which Turbiscan Lab is used to determine the cloud point temperature. |
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| Keywords: | Triblock copolymers cloud point poly(N-vinylcaprolactam) poly(t-butyl acrylate) poly(acrylic acid) multiple light scattering |
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