نوع مقاله : پژوهشی
نویسندگان
بابلسر، داﻧﺸﮕﺎه ﻣﺎزﻧﺪران، داﻧﺸﮑﺪه ﻓﻨﯽ و فناوری، ﮔﺮوه ﻣهندسی ﺷﯿمی
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Hypothesis: Polyolefin elastomer (POE) improves flexibility by increasing free volume and chain mobility; however, it simultaneously reduces melt viscosity and strength, which can impair cell stability during the foaming process. Conversely, nanoclay is hypothesized to create numerous nucleation sites through a nucleating mechanism and increase interfacial melt viscosity by acting as a physical barrier and restricting chain mobility. The present study focuses on developing an optimized base formulation of LDPE suitable for foam applications rather than the direct fabrication of foam structures.
Methods: To investigate the synergistic effects of nanoclay and polyolefin elastomer, low-density polyethylene was mixed with varying concentrations of both components. In this regard, the Design of Experiments software was employed by considering the adjustable ranges of polyolefin elastomer and nanoclay based on the literature. Samples with different material compositions were compounded using a twin-screw extruder and then injection-molded into dumbbell-shaped specimens. Melt flow index, differential scanning calorimetry, and tensile tests were subsequently carried out. The interaction effects of polyolefin elastomer and nanoclay concentrations on the melt flow index, melting temperature, modulus, and tensile strength of low-density polyethylene were further analyzed using three-dimensional plots generated by Design of Experiments software.
Findings: The results indicate that within the investigated concentration range, the effect of polyolefin elastomer concentration on the melt flow index of low-density polyethylene was independent of the presence of nanoclay. In other words, increasing the polyolefin elastomer level increased the melt flow index at both low and high nanoclay loadings. Also, the maximum melting temperature (117 °C), modulus (19.3 MPa), and tensile force at break (151 N) of low-density polyethylene were achieved at the highest nanoclay (0.2 phr) and polyolefin elastomer (5 phr) concentrations.
کلیدواژهها [English]
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