Injection molding morphological models

Hierarchical fibrillar model [80] This model was proposed for drawn TLCP fibers. They are composed of bundles of macro fibrils (5 p,m), fibrils (0.5 (Jim), and micro fibrils (0.05 p.m) in a hierarchical order (see Figure 8.17). This type of highly oriented fibrillar morphology is also found in the inner skin region of the injection-molded parts, as illustrated in Figure 8.18. 

Four-layer model [82] The morphology of the injection-molded bar of Ul-trax KR 4002 (all-aromatic TLCP from BASF) is composed of four distinct layers highly oriented skin layer, weakly oriented sub-skin layer, highly... 

Five-layer model [83] The morphology of injection-molded bars of a TLCP, para-acetoxybenzoic acid and para-acetoxynaphthoic acid (70/30),... 

Hsiung and Cakmak developed a structure-oriented model to simulate the crystalline structure developed in the injection molding of SPS [107]. Their model was elaborated by taking a Lagrangian approach and a three-dimensional mold geometry. The morphological structure of the SPS sample molded at a particular condition quantitatively matches the experimental observations. 

Pantani et al. [11] gave an extensive review on available models to predict and characterize the morphology of injection-molded parts. The authors themselves proposed a model to predict the morphology of injection-molded iPP, in which flow kinematics are computed using a lubrication approximation. Polymorphism was accounted for, using the Avrami-Evans-Nakamura equation to describe the crystallization kinetics of the mesomorphic phase, while the evolution of the a phase was modeled using Kolmogorov s model [122]. 

Based on the theoretical analysis about the morphology and the etfeet of crystallinity on the development of residual stresses for injection molded crystalline polymers, the residual stresses have been simulated by means of a new four elements viscoelastic mechanical model. Considering the crystalline orientation of injection molded parts, we view the parts as orthotropic solids to simulate the development of residual stresses in both longitudinal and transverse directions of the parts. 

Surface morphology and dispersion of CNTs was investigated on cryofractured injection molded impact bar samples using a field emission HRSEM (Model JEOL JSM-7401 F). 

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