Beijing Engineering Research Centre of Advanced Structural Transparencies for the Modern Traffic System, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
The effects of melt temperature on the residual stress of thermoplastic polyurethane(TPU)sheets during the injection molding process were studied by birefringence. The results indicate that the residual stress in the near gate area is higher than that in the far gate area and decreases with the increase of the melt temperature. The residual stress of cross section in the two directions is characterized. The injection molded TPU sheets have obvious skin-core structure and zero stress layer. The thickness of core layer increases with the melt temperature rising. The results of residual stress analysis show that the residual stress of core layer is dominated by the flow residual stress, while it is the result of superposition of flow and thermal residual stress in the surface layer. Besides, the warpage deformation is directly related to the distribution of residual stress. The change of the dimensions of the TPU sheets is directly caused by the release of flow residual stress.
TANG Y F . Brief description for synthesis methods and applications of adhesion type TPU[J]. Chemical Propellants & Polymeric Materials, 2016, 14 (3): 9- 14.
3
CHARLON M , HEINRICH B , MATTER Y , et al. Synthesis, structure and properties of fully biobased thermoplastic polyurethanes, obtained from a diisocyanate based on modified dimer fatty acids, and different renewable diols[J]. European Polymer Journal, 2014, 61, 197- 205.
doi: 10.1016/j.eurpolymj.2014.10.012
4
BARTOLOME L , AURREKOETXEA J , URCHEGUI M A , et al. The influences of deformation state and experimental conditions on inelastic behaviour of an extruded thermoplastic polyurethane elastomer[J]. Materials & Design, 2013, 49, 974- 980.
5
KULL L K , BASS R W , CRAFT G , et al. Synthesis and characterization of an ultra-soft poly (carbonate urethane)[J]. European Polymer Journal, 2015, 71, 510- 522.
doi: 10.1016/j.eurpolymj.2015.08.015
6
ZHANG L H , YAO X H , ZANG S G , et al. Temperature and strain rate dependent tensile behavior of a transparent polyurethane interlayer[J]. Materials & Design, 2015, 65, 1181- 1188.
LI H M , LI R B , CHEN J T , et al. Introduction to stress during injection molding process[J]. Journal of Netshaps Forming Engineering, 2016, 40 (1): 20- 26.
8
GUEVARA M A , FIGUEROA L . Residual stresses in injection molded products[J]. Journal of Materials Science, 2014, 49 (13): 4399- 4415.
doi: 10.1007/s10853-014-8170-y
9
XIE P , GUO F , JIAO Z , et al. Effect of gate size on the melt filling behavior and residual stress of injection molded parts[J]. Materials & Design, 2014, 53, 366- 372.
HAN J , SHEN C Y , LIU C T , et al. Flow induced birefringence of weldline region in polystyrene injection molding[J]. Journal of Chemical Industry and Engineering (China), 2008, 59 (5): 1305- 1309.
doi: 10.3321/j.issn:0438-1157.2008.05.037
CHEN Y H , YUAN Y , LI X , et al. Residual stress of injection molded and injection compression molded auto glazing[J]. Journal of Aeronautical Materials, 2010, 30 (3): 48- 54.
doi: 10.3969/j.issn.1005-5053.2010.3.011
WANG Z H , XIN Y . Effect of injection velocity on optical properties of high transmittance PMMA injection molded parts[J]. Engineering Plastics Application, 2017, 45 (2): 64- 68.
doi: 10.3969/j.issn.1001-3539.2017.02.014
XI G D , ZHOU H M , LI D Q . Effect of processing conditions on residual stress and shrinkage in injection molding[J]. Journal of Chemical Industry and Engineering (China), 2007, 58 (1): 248- 254.
doi: 10.3321/j.issn:0438-1157.2007.01.041
GE Y , WANG T , LI L . Effect of injection molding parameters on residual stress of polycarbonate[J]. Journal of Materials Engineering, 2014, (1): 24- 29.
doi: 10.3969/j.issn.1001-4381.2014.01.005
15
ISAYEV A I . Orientation development in the injection molding of amorphous polymers[J]. Polymer Engineering and Science, 1983, 23 (5): 271- 284.
doi: 10.1002/pen.760230507
16
ISAYEV A I , CROUTHAMEL D L . Residual stress development in the injection molding of polymers[J]. Journal of Macromolecular Science, 1984, 22 (2): 177- 232.
17
WANG H , ZHOU H , HUANG Z , et al. Experimental investigation and modeling of the mechanical behavior of PC/ABS during monotonic and cyclic loading[J]. Polymer Testing, 2016, 50, 216- 223.
doi: 10.1016/j.polymertesting.2015.12.010
HUANG X H , ZHOU C X , CAO Y G . Orientation and residual stress in injection-molded polystyrene[J]. Polymer Materials Science and Engineering, 2000, 16 (5): 131- 133.
doi: 10.3321/j.issn:1000-7555.2000.05.036
19
XIANG N , ZHANG X , LIU H , et al. Microstructure and tensile properties of injection molded thermoplastic polyurethane with different melt temperatures[J]. Journal of Applied Polymer Science, 2020, 137 (29): 48891.
doi: 10.1002/app.48891
HAN J , LI G , CHEN J B , et al. Simulation experiment study of influence factors on residual stresses of injection-molded parts[J]. China Plastics Industry, 2007, 35 (2): 28- 30.
QIU Q J , JIANG B Y , CHEN L , et al. Study on thermal residual stress of injection compression molded thin-walled plastic part by simulation[J]. China Plastics Industry, 2012, 40 (7): 41- 45.
22
刘树. 聚氨酯弹性体的取向行为[J]. 合成橡胶工业, 1991, (6): 437- 442.
22
LIU S . Orientation behaviors of block polyurethanes[J]. Synthetic Rubber Industry, 1991, (6): 437- 442.