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Licensed Unlicensed Requires Authentication Published by De Gruyter August 1, 2019

Study on Influence of Co-Injection Molding Process on Self-Reinforcing Characteristics of Self-Reinforced Polypropylene Composite via Visualization

K.-Y. Jiang , Y. Zhang , L. Yang and Y. Lu


Self-reinforced polymer composites (SRCs), which are fabricated by combining the same type of polymer with different properties into one body, have high specific strength, no interfacial heterogeneity, and ease of recycling. To better understand the relationship between the molding process and mechanical properties of SRCs, the co-injection molding process was used in this study to process SRCs samples. Further, a self-developed visualized experimental device was used to observe the flow of the polymer melt directly during co-injection molding. From the visualization results, it was found that the tensile properties of SRCs are positively correlated with the absolute value of the slopes of the velocity change at lower melt temperature. When the melt temperature increases to a certain degree, the tensile properties of SRCs are much lower than that of lower melt temperature. The shear rate inside the melt flow and the shear rate between the melt and the matrix wall play a major role in the self-reinforcing characteristics of the SRC.

*Correspondence address, Mail address: Kaiyu Jiang, Engineering Research Center of Plastic Molding Products of Ministry of Education, Dalian University of Technology, Dalian 116024, PRC, E-mail:


Andrzejewski, J., Szostak, M., Barczewski, M., Krasucki, J. and Sterzynski, T., “Fabrication of the Self-Reinforced Composites Using Co-Extrusion Technique”, J. Appl. Polym. Sci., 131, 41180 (2014) 10.1002/app.41180Search in Google Scholar

Čermák, R., Obadal, M., Habrová, V., Stoklasa, K., Verney, V., Commereuc, S. and Fraïsse, F., “Self-Reinforcement of Polymers as a Consequence of Elongational Flow”, Rheol. Acta, 45, 366373 (2006) 10.1007/s00397-005-0052-4Search in Google Scholar

Diaz, J. A., Youngblood, J. P., “Multivariable Dependency of Thermal Shrinkage in Highly Aligned Polypropylene Tapes for Self-Reinforced Polymer Composites”, Composites Part A, 90, 771777 (2016) 10.1016/j.compositesa.2016.09.004Search in Google Scholar

Dubbeldam, J. L. A., Molenaar, J., “Dynamics of the Spurt Instability in Polymer Extrusion”, J. Non-Newtonian Fluid. Mech., 112, 217235 (2003) 10.1016/s0377-0257(03)00101-0Search in Google Scholar

Gao, C. C., Yu, L., Liu, H. S. and Chen, L., “Development of Self-Reinforced Polymer Composites”, Prog. Polym. Sci., 37, 767780 (2012) 10.1016/j.progpolymsci.2011.09.005Search in Google Scholar

Han, L., Xu, H., Sui, X. F., Zhang, L. P., Zhong, Y. and Mao, Z. P., “Preparation and Properties of Poly(e-caprolactone) Self-Reinforced Composites Based on Fibers/Matrix Structure”, J. Appl. Polym. Sci., 134, 44673 (2017) 10.1002/app.44673Search in Google Scholar

Hine, P., Ward, I., Olley, R. and Bassett, D., “The Hot Compaction of High Modulus Melt-Spun Polyethylene Fibers”, J. Mater. Sci., 28, 316324 (1993) 10.1007/bf00357801Search in Google Scholar

Jerpdal, L., Ståhlberg, D. and Åkermo, M., “Influence of Fibre Stretching on the Microstructure of Self-Reinforced Poly(ethylene terephthalate) Composite”, J. Reinf. Plast. Compos., 35, 16341641 (2016) 10.1177/0731684416662328Search in Google Scholar

Jiang, J., Liu, X. H., Lian, M., Pan, Y. M., Chen, Q., Liu, H., Zheng, G. Q., Guo, Z. H., Schubert, D. W., Shen, C. Y. and Liu, C. T., “Self-Reinforcing and Toughening Isotactic Polypropylene via Melt Sequential Injection Molding”, Polym. Test., 67, 183189 (2018) 10.1016/j.polymertesting.2018.03.005Search in Google Scholar

Jiang, K. Y., Ji, Z., Li, H., Wang, M. J. and Yu, T. M., “Polymer Flow Behavior Analysis Based on Physical Visualization Technology for Ultrasonic Vibration-Assisted Injection Molding”, Int. Polym. Proc., 32, 290297 (2017) 10.3139/217.3183Search in Google Scholar

Jiang, K. Y., Tian, J. N., Wang, M. J., Ma, J. J. and Yu, Z. K., “Influence of Scale Effect on Filling Behavior of Injection Molding by Visualization Method”, Int. Polym. Proc., 27, 2530 (2012) 10.3139/217.2497Search in Google Scholar

Jin, Z. M., Zhu, F. H. and Gao, F. R., “Visualization Study of the Plastication during Injection Molding (I)”, Chn. Plast., 17, 8690 (2003)Search in Google Scholar

Kmetty, Á., Bárány, T. and Karger-Kocsis, J., “Self-Reinforced Polymeric Materials: A Review”, Prog. Polym. Sci., 35, 12881310 (2010) 10.1016/j.progpolymsci.2010.07.002Search in Google Scholar

Liang, J. Z.: Processing Rheology of Polymer Materials, 1st Edition, National Defense Industrial Publishers, Beijing, PRC (2008)Search in Google Scholar

Lu, S. F., Wang, L. X. and Shen, C.Y., “Influence of Process Parameters and Flow Direction on Strength of Injection Molded Parts”, Polym. Mater. Sci. Eng., 29, 5154 (2013)Search in Google Scholar

Mai, F., Tu, W., Bilotti, E. and Peijs, T., “Preparation and Properties of Self-Reinforced Poly(lactic acid) Composites Based on Oriented Tapes”, Composites Part A, 76, 145153 (2015) 10.1016/j.compositesa.2015.05.030Search in Google Scholar

Nguyen, B. N., Bapanapalli, S. K., Holbery, J. D., Smith, M. T., Kunc, V., Frame, B. J., Phelps, J. H. and TuckerIII, C. L., “Fiber Length and Orientation in Long-Fiber Injection-Molded Thermoplastics-Part1: Molding of Microstructure and Elastic Properties”, J. Compos. Mater., 42, 10031029 (2008) 10.1177/0021998308088606Search in Google Scholar

Schneider, C., Kazemahvazi, S., Åkermo, M. and Zenkert, D., “Compression and Tensile Properties of Self-Reinforced Poly(ethylene terephthalate)-Composites”, Polym. Test., 32, 221230 (2013) 10.1016/j.polymertesting.2012.11.002Search in Google Scholar

Shi, S. Y., Wang, L. N., Xu, W. Z., Zheng, G. Q. and Shen, C. Y., “The Structure and Mechanical Property of Micro-Injection Molded HDPE Parts”, J. Zhengzhou Univ. (Eng. Sci.), 37, 2433 (2016)Search in Google Scholar

Somord, K., Suwantong, O., Tawichai, N., Peijs, T. and Soykeabkaew, N., “Self-Reinforced Poly(lactic acid) Nanocomposites of High Toughness”, Polymer, 103, 347352 (2016) 10.1016/j.polymer.2016.09.080Search in Google Scholar

Swolfs, Y., Zhang, Q., Baets, J. and Verpoest, I., “The Influence of Process Parameters on the Properties of Hot Compacted Self-Reinforced Polypropylene Composites”, Composites Part A, 65, 3846 (2014) 10.1016/j.compositesa.2014.05.022Search in Google Scholar

Vadas, D., Kmetty, Á., Bárány, T., Marosi, G. and Bocz, K., “Flame Retarded Self-Reinforced Polypropylene Composites Prepared by Injection Moulding”, Polym. Adv. Technol., 29, 433441 (2018) 10.1002/pat.4132Search in Google Scholar

Wang, J., Chen, J. N. and Dai, P., “Hot Pressing Process and Properties of Polyethylene Naphthalate Single-Polymer-Composites”, Mater. Sci. Technol., 20, 104107 (2012)Search in Google Scholar

Wang, L. F., Jiang, K. Y. and Yang, L., “In Mold Self-Reinforced Molding Method of Single Polymer Composites”, Die Mould Manuf., 16, 4144 (2016)Search in Google Scholar

Yokoi, H.Visualization and Measurement Technologies inside Injection Mold”. Int. J. Jpn. Soc. Precis. Eng., 73, 188192 (2007) 10.2493/jjspe.73.188Search in Google Scholar

Yoshimoto, E., Kato, H., Shibuya, A., Masuda, N. and Yokoi, H., “Visualization Analysis on a Transcription Molding Process of Cavity the Surface State for Cyclic Olefin Copolymer”, Int. J. Jpn. Soc. Form. Proc., 23, 6369 (2011) 10.4325/seikeikakou.23.63Search in Google Scholar

Zhao, Z. H., Chen, J. N., “Research Development of Single Polymer Composite Preparation”, Eng. Plast. Appl., 38, 8183 (2010)Search in Google Scholar

Received: 2018-10-16
Accepted: 2019-03-28
Published Online: 2019-08-01
Published in Print: 2019-08-13

© 2019, Carl Hanser Verlag, Munich

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