Yes / The microstructure and molecular orientation distribution over both the length and the thickness of microinjection‐molded linear low‐density polyethylene with a weld line were characterized as a function of processing parameters using small‐angle X‐ray scattering and wide‐angle X‐ray diffraction techniques. The weld line was introduced via recombination of two separated melt streams with an angle of 180° to each other in injection molding. The lamellar structure was found to be related to the mold temperature strongly but the injection velocity and the melt temperature slightly. Furthermore, the distributions of molecular orientation at different molding conditions and different positions in the cross section of molded samples were derived from Hermans equation. The degree of orientation of polymeric chains and the thickness of oriented layers decrease considerably with an increase of both mold temperature and melt temperature, which could be explained by the stress relaxation of sheared chains and the reduced melt viscosity, respectively. The level of molecular orientation was found to be lowest in the weld line when varying injection velocity, mold temperature, and melt temperature, thus providing an effective means to identify the position of weld line induced by flow obstacles during injection‐molding process. / Jilin Scientific and Technological Development Program. Grant Number: 20180519001JH; National Key R&D Program of China. Grant Number: 2018YFB0704200; National Natural Science Foundation of China. Grant Numbers: 21674119, 21790342; Newton Advanced Fellowship of Royal Society. Grant Number: NA150222
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/17637 |
| Date | 31 January 2020 |
| Creators | Liao, T., Zhao, X., Yang, X., Whiteside, Benjamin R., Coates, Philip D., Jiang, Z., Men, Y. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Accepted manuscript |
| Rights | © 2020 Wiley. This is the peer-reviewed version of the following article: Liao T, Zhao X, Yang X et al (2019) Predicting the location of weld line in microinjection-molded polyethylene via molecular orientation distribution. Journal of Polymer Science, Part B: Polymer Physics. 57(24): 1705-1715., which has been published in final form at https://doi.org/10.1002/polb.24905. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. |
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