Análise estatística das propriedades mecânicas de resistência à tração de polímeros termoplásticos (EVA, PEBD, PP) após exposição a diferentes solventes químicos
Statistical analysis of the tensile strength mechanical properties of thermoplastic polymers (EVA, LDPE, PP) after exposure to different chemical solvents
Lara Vasconcellos Ponsoni, Marina Kauling de Almeida, Kristian Madeira, Gustavo Pacheco Militão, Eduardo Junca, Matheus Vinicius Gregory Zimmermann
Resumo
A resistência química de polímeros termoplásticos é fundamental para garantir sua durabilidade em aplicações industriais. Neste estudo, avaliou-se o comportamento de PP, EVA e PEBD após exposição a acetona, pentano, hidróxido de sódio, ácido acético e ácido sulfúrico por 24 e 48 horas. Corpos de prova moldados por injeção (ASTM D638-03) foram submetidos a ensaios de tração, com análise estatística por ANOVA, teste t e Tukey (α = 0,05). O EVA apresentou maior sensibilidade, com reduções marcantes no módulo elástico e na tensão máxima, especialmente para o pentano, que diminuiu a tensão de 23,02 MPa (puro) para 11,68 MPa (24 h) e o módulo de 22,96 MPa para 9,52 MPa (24 h). O PEBD e o PP mostraram resistência moderada, embora mais afetados por solventes apolares; no PEBD, o módulo caiu de 40,71 MPa para 21 MPa (pentano), enquanto no PP a redução foi menos intensa, de 596,61 para 445,68 MPa. As diferenças entre 24 e 48 horas foram pequenas, sugerindo que a degradação mecânica ocorre majoritariamente nas primeiras 24 horas. Os resultados reforçam a importância da composição polimérica, da polaridade do solvente e do tempo de exposição no projeto de materiais para ambientes quimicamente agressivos.
Palavras-chave
Abstract
The chemical resistance of thermoplastic polymers is essential to ensure their durability in industrial applications. In this study, the behavior of PP, EVA, and LDPE was evaluated after exposure to acetone, pentane, sodium hydroxide, acetic acid, and sulfuric acid for 24 and 48 hours. Injection-molded test specimens (ASTM D638-03) were subjected to tensile tests, with statistical analysis by ANOVA, t-test, and Tukey (α = 0.05). EVA showed greater sensitivity, with marked reductions in elastic modulus and maximum stress, especially for pentane, which decreased stress from 23.02 MPa (pure) to 11.68 MPa (24 h) and modulus from 22.96 MPa to 9.52 MPa (24 h). LDPE and PP showed moderate resistance, although they were more affected by nonpolar solvents; in LDPE, the modulus fell from 40.71 MPa to 21 MPa (pentane), while in PP the reduction was less intense, from 596.61 to 445.68 MPa. The differences between 24 and 48 hours were small, suggesting that mechanical degradation occurs mainly in the first 24 hours. The results reinforce the importance of polymer composition, solvent polarity, and exposure time in the design of materials for chemically aggressive environments.
Keywords
References
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Submitted date:
08/26/2025
Accepted date:
01/09/2026
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