Ternary segmented polyurethanes: morphology and kinetics of the crystallization

Autor(es)

André Sanches Bevilacqua ^[1] ; Rafael Bergamo Trinca ^[2] ; Maria Isabel Felisberti ^[3]

Afiliação do(s) autor(es)

^[1] Universidade Estadual de Campinas. Instituto de Química - Brasil

^[2] Universidade Estadual de Campinas. Instituto de Química - Brasil

^[3] Universidade Estadual de Campinas. Instituto de Química - Brasil

• Tipo de documento: Artigo Científico
• Fonte: POLIMEROS-CIENCIA E TECNOLOGIA; v. 33, n. 1 2023-05-19.

Resumo

Abstract Segmented polyurethanes based on poly(l-lactide)diol - PLLA, poly(ethylene-glycol) - PEG, poly(trimethylene-carbonate)diol - PTMC and hexamethylene diisocyanate were synthesized by a two-step polyaddition. Polyurethanes with variable compositions and molar mass were semi-crystalline and presented PLLA or PLLA + PEG crystalline phases and a heterogeneous amorphous phase. Sequential crystallization of PLLA and PEG resulted in a confined PEG crystallization into the PLLA crystalline phase. The random distribution of the segments in the polymer chains and the partial miscibility of the segments in the amorphous phase strongly influenced the morphology of the crystalline phase, and the kinetics of the crystallization. Morphology changed from not well-defined spherulites with Maltese cross to ring banded spherulites and axialites as the PLLA mass fraction decreased. PLLA nucleation and crystal growth rates varied with crystallization temperature similarly to homopolymers, presenting a bell-shaped curve, and the temperature for the maximum growth rate dependent on the polyurethanes composition. (AU)

• Processo FAPESP: 15/25406-5 - Organizando a matéria: colóides formados por associação de surfactantes, polímeros e nanopartículas
• Beneficiário: Watson Loh
• Modalidade de apoio: Auxílio à Pesquisa - Temático