Influence of mold cavity thickness on electrical, morphological and thermal properties of polypropylene/carbon micromoldings
Author:
Zhou Shengtai1, Jiang Renze2, Lei Xue1, Zou Huawei1, Hrymak Andrew N.2
Affiliation:
1. The State Key Laboratory of Polymer Materials Engineering , Polymer Research Institute, Sichuan University , Chengdu , China 2. Department of Chemical and Biochemical Engineering , The University of Western Ontario , London , Canada
Abstract
Abstract
In this work, a comparative study on the electrical conductivity (σ) and thermal properties of polypropylene (PP)/carbon microparts with different part thickness (namely, 0.85 and 0.50 mm) is reported. Two different types of carbon filler (i.e., CNT and CB) were adopted to study the efficacy of different carbon fillers in improving the σ of PP/carbon microparts. In general, the σ of 0.85 mm thickness microparts were higher than the 0.50 mm thickness microparts, regardless of the carbon filler type and testing directions. This suggested that higher shearing conditions that prevailed in the microinjection molding (μIM) process were unfavorable for the formation of intact conductive pathways in corresponding moldings, albeit the distribution of carbon fillers turned better with increasing shear rates, as confirmed by morphology observations. Differential scanning calorimetry results showed that prior thermomechanical histories (including melt blending and μIM) experienced by the polymer melts had an influence on the thermal behavior of subsequent moldings. Also, there existed a strong shear flow-induced crystallization of polymer chains during μIM because the crystallinity of microparts was higher than that of feed materials.
Funder
Natural Sciences and Engineering Research Council of Canada Discovery Grants National Natural Science Foundation of China China Postdoctoral Science Foundation Ontario Graduate Scholarship Queen Elizabeth II Graduate Scholarship
Publisher
Walter de Gruyter GmbH
Subject
Materials Chemistry,Industrial and Manufacturing Engineering,Polymers and Plastics,General Chemical Engineering
Reference52 articles.
1. Abbasi, S., Carreau, P.J., and Derdouri, A. (2010). Flow Induced orientation of multiwalled carbon nanotubes in polycarbonate nanocomposites: Rheology, conductivity and mechanical properties. Polymer 51: 922–935, https://doi.org/10.1016/j.polymer.2009.12.041. 2. Al-Saleh, M.H., Gelves, G.A., and Sundararaj, U. (2011). Copper nanowire/polystyrene nanocomposites: lower percolation threshold and higher EMI shielding. Compos. Part A 42: 92–97, https://doi.org/10.1016/j.compositesa.2010.10.003. 3. Ameli, A., Kazemi, Y., Wang, S., Park, C.B., and Pötschke, P. (2017). Process-microstructure-electrical conductivity relationships in Injection-molded polypropylene/carbon nanotube nanocomposite foams. Compos. Part A 96: 28–36, https://doi.org/10.1016/j.compositesa.2017.02.012. 4. Anass, B., Boutaous, M., El Otmani, R., El Hakimi, A., Touache, A., Kamal, M.R., Derdouri, S., Refaa, Z., and Siginer, D.A. (2020). Simulation of crystallization evolution of polyoxymethylene during microinjection molding cycle. Polym. Adv. Technol. 31: 838–852, https://doi.org/10.1002/pat.4819. 5. Arvidson, S.A., Khan, S.A., and Gorga, R.E. (2010). Mesomorphic-α-monoclinic phase transition in Isotactic polypropylene: a study of processing effects on structure and mechanical properties. Macromolecules 43: 2916–2924, https://doi.org/10.1021/ma1001645.
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