TY - JOUR
T1 - Influence of process-induced shrinkage and annealing on the thermomechanical behavior of glass fiber-reinforced polypropylene
AU - Mulle, Matthieu
AU - Wafai, Husam
AU - Yudhanto, Arief
AU - Lubineau, Gilles
AU - Yaldiz, R.
AU - Schijve, W.
AU - Verghese, N.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1315-01-01
Acknowledgements: The research reported in this publication was supported by the Saudi Arabia Basic Industries Corporation (SABIC-Netherlands) under Grant Agreement number RGC/3/2050-01-01 and by King Abdullah University of Science and Technology (KAUST-Saudi Arabia), under award number BAS/1/1315-01-01. The authors are very grateful to Faisal K. Kamal and Mohammed S. Almulhim for their precious technical support.
PY - 2018/12/6
Y1 - 2018/12/6
N2 - We investigate the influence of process-induced shrinkage and subsequent annealing on the thermomechanical behavior of unidirectional laminates made of continuous glass fiber-reinforced polypropylene (GFPP). We use two different industrial lamination processes: static hot-press (SHP), and double-belt press (DBP) that are characterized by different cooling rates and pressure levels and most importantly, by the use of a closed mold in the case of SHP manufacturing. We measure the longitudinal and transverse shrinkage during the manufacturing and annealing processes using embedded fiber Bragg gratings (FBGs). The SHP molding reveals much lower induced shrinkage in GFPP as compared to the DBP process, although the relatively slow cooling should promote a higher degree of crystallization. We ascribe this to the constraining effect of the metallic mold used with the SHP process. The poor thermal conductivity of the mold is also responsible for a layer-like crystal microstructure in the GFPP matrix, causing a specific relaxation effect during the post-process heating treatment. Annealing generates additional shrinkage that is due to an increased degree of crystallinity and to the partial relaxation of residual stresses. However, the thermal expansion properties remain impacted by the process-induced strain state of the GFPP laminates and are still process-dependent after annealing.
AB - We investigate the influence of process-induced shrinkage and subsequent annealing on the thermomechanical behavior of unidirectional laminates made of continuous glass fiber-reinforced polypropylene (GFPP). We use two different industrial lamination processes: static hot-press (SHP), and double-belt press (DBP) that are characterized by different cooling rates and pressure levels and most importantly, by the use of a closed mold in the case of SHP manufacturing. We measure the longitudinal and transverse shrinkage during the manufacturing and annealing processes using embedded fiber Bragg gratings (FBGs). The SHP molding reveals much lower induced shrinkage in GFPP as compared to the DBP process, although the relatively slow cooling should promote a higher degree of crystallization. We ascribe this to the constraining effect of the metallic mold used with the SHP process. The poor thermal conductivity of the mold is also responsible for a layer-like crystal microstructure in the GFPP matrix, causing a specific relaxation effect during the post-process heating treatment. Annealing generates additional shrinkage that is due to an increased degree of crystallinity and to the partial relaxation of residual stresses. However, the thermal expansion properties remain impacted by the process-induced strain state of the GFPP laminates and are still process-dependent after annealing.
UR - http://hdl.handle.net/10754/630666
UR - https://www.sciencedirect.com/science/article/pii/S0266353818318840
UR - http://www.scopus.com/inward/record.url?scp=85057747367&partnerID=8YFLogxK
U2 - 10.1016/j.compscitech.2018.12.005
DO - 10.1016/j.compscitech.2018.12.005
M3 - Article
VL - 170
SP - 183
EP - 189
JO - Composites Science and Technology
JF - Composites Science and Technology
SN - 0266-3538
ER -