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Residual orientation in injection‐moulded plaques of atactic‐polystyrene I: The effect of processing conditions
Author(s) -
Healy John,
Knott Robert,
Edward Graham
Publication year - 2018
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24710
Subject(s) - materials science , polystyrene , composite material , injection moulding , orientation (vector space) , residual , polymer , core (optical fiber) , geometry , mathematics , algorithm , computer science
Injection moulded polymer articles often have residual macromolecular or crystalline orientation which can have a significant impact on the optical and mechanical properties of the moulded article. Small angle neutron scattering (SANS) was used to measure the molecular shape and orientation of deuterated blends of injection moulded polystyrene. For ∼1‐mm‐thick mouldings of uniform rectangular cross‐section, the eccentricity in the SANS pattern gave a direct measure of the residual molecular orientation over the length scale ∼100–1,500 Å. The residual orientation was found to vary significantly with injection moulding conditions with comparative residual orientation decreasing with decreasing mould fill‐time, and increasing with mould thickness and moulding temperatures. The orientation was found to be a minimum in the centre of the mould and highest near the surface and the average orientation at a particular position in the mould was found to be strongly correlated with the volume of material deposited as a solid skin layer during injection moulding. POLYM. ENG. SCI., 58:1322–1331, 2018. © 2017 Society of Plastics Engineers