The orientation of polymer chains after Injection Molding is usually studied using techniques that measure the average orientation of a polymer segment. Small-angle neutron scattering (SANS) is a technique for measuring orientation at molecular scales and is very sensitive to molecular anisotropy. The residual orientation and conformation of polyethylene and polystyrene chains after injection micro-molding has been measured using SANS. We have found that, for micro-moldings, the residual orientation decreases with increasing injection speed and that the residual chain orientation at the molecular scale is not necessarily related to the average orientation of short chain segments.
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