Injection molding compositions

Fig. 6.8. Fracture toughness, K, of short glass fiber-thermoplastics injection molded composites as a function of weight fraction of fiber, fVr. (O) and (A) polyethylene terephthalate (PET) matrix ( ) and (A) polycarbonate (PC) matrix. Notches made transverse (O, ) and parallel (A, A) to the mold fill direction,...

Fig. 6.9. Normalized fracture toughness, (Kc - AKQ)/K. of short glass fiber-thermoplastics injection molded composites as a function of reinforcing effectiveness parameter, ft (O) polyetheretherketone (PEEK) matrix (K = 6.5 MPa m) (A) polytetrafluoroethylene (PTFE) matrix (K = 1.9 MPaym).

In injection molded composites of polypropylene containing short glass fibers, the fiber orientation depended on the flow pattern (which, in turn, is related to mold thickness, the position of the gate, and flow rate)." Substantial variation was detected along the thickness of the sample. Crystallites followed a pattern of fiber distribution but they grew in a direction perpendicular to the direction of the fiber and specimen surface. The direction of spherulite growth was different in neat resin where crystallites grew parallel to the surface of the mold (specimen). 

Poly(butylene terephthalate) (PBT) is semicrystalline polyester commonly used in injection molding, composite, and blend applications. Some typical properties are Glass Transition Temperature, Tg = 66°C Melting Temperature, Tm = 227° C Molecular weight of repeat unit = 220.23 g/mole. 

Figure15.12 Comparison betweenwoodflourandwoodfiberasareinforcementin polypropylene. Injection molded composites. 3% maleated polypropylene added as a coupling agent. (Derived from Ref. [52].)...

HG Kalian. Two-Dimensional Mapping of Tensile Strength for Injection Molded Composites of Glass Tiber Reinforced Polypropylene. ANTEC, SPE, Toronto, 1997, pp 1832-1836. 

Silverman characterized flexural creep resistance at 120°C (33) and room temperature impact resistance (34) for test specimens from injection-molded composites of chopped fibers versus machined specimens from compression molded continuous long GFR polypropylene sheets. His concepts of glass fiber reinforcement in stampable composites tend to mirror many of the attributes related to megacoupling of short GFRP. 

HG Karian, K Stoops. Two-dimensional mapping of tensile strength for injection molded composites of glass fiber reinforced polypropylene. Polym Compos 19(1) 1-6, 1998. 

Karger-Kocsis, J. (1991) Stmcture and Fracture Mechanics of Injection-molded Composites, in International Encyclopedia of Composites, Vol. 5, (ed. S.M. Lee), VCH, New York, pp. 337-356. 

Consider a set of typical values in the injection molded composites (p — 10%, Ur = 20, Cj — O.OOland s = 0.01. FromEqs. 5.48 and 5.50, assmning the fibers are aligned, we obtain Np = 6.4 and (5 = 0.1. Then we have Np3 = 0.064. The flow belongs to regime one, and hence decoupled flow and fiber orientation calculations will be allowed. This will be the case for many, but not all, injection molding simulations for fiber-filled composites. 

Equation 6.20 is the required equation for the effective stiffness tensor Cyia-Since Cp, Cp and q/ are all known, one only needs to find the strain-eoneen-tration tensor Ayu- Different expressions of Ayi i represent different models. Many models have been reviewed by Tucker and Liang (1999). They recommend the Mori-Tanaka model as the best choice for injection molded composites. The model was proposed by Mori and Tanaka (1973) and has later been described by Benveniste (1987) and Christensen (1990) in a simpler direct way. The Mori-Tanaka strain-concentration tensor is given by... 

Baltussen MGHM, Hulsen MA, Peters GWM (2010) Numerical simulation of the fountain flow instability in injection molding. J Non-Newtonian Fluid Mech 165 631-640 Batoz JL, Lardeur P (1989) A discrete shear triangular nine d.o.f element for the analysis of thick to very thin plates. Int J Numer Meth Eng 28 533-560 Bay RS (1991) Orientation in injection molded composites A comparison of theory and experiment. Ph.D Thesis, University of Illinois, Uibana, II Benveniste Y (1987) A new approach to the application of Mori-Tanaka s theory in composite materials. Mech Mater 6 147-157... 

Butyraldehyde is a reactant in the manufacture of n-butanol, 2-ethyl 1-hexanol, butylamines, and trimethylolpropane. It is used as an intermediate in the production of synthetic resins, rubber accelerators, solvents, and plasticizers. Reaction of n-butyraldehyde with polyvinyl alcohol yields polyvinyl butyral which is useful in safety glass, fabric coatings, and injection molding compositions. Isobutyraldehyde is used in the manufacture of isobutanol, neopentyl glycol, and isobutyl acetate. The isobutyraldehyde is an intermediate in the production of rubber antioxidants and accelerators, slow-release nitrogen fertilizers, and isobutyric acid. 

Figure 5.19. TEM micrographs of injection molded composites with 2 wt% MWCNTs in polycarbonate in the near of the mold wall (center of plate geometry with 80x80x 2 mm and a film gate) (a) IMl 150 mm/s (injection velocity), 280°C (melt temperature), 40 bar (holding pressure) and 60°C (mold temperature) as well as (b) IM2 10 mm/s, 320°C, 40 bar and 100°C...

Figure 5.27. Electrical conductivities of injection molded composites with (a) 2 wt% and (b) 5 wt% MWCNTs in polycarbonate according to the parameter sets of Table 5.3 [46]...

Figure 1 Volume resistivity versus volume fraction of aluminum flakes in various polymers. Open symbols represent injection-molded composites with 50 1 aspect ratio flakes. Filled symbols represent compression-molded composites 16.7 1 aspect ratio flakes. ( , ) polypropylene, (A) polycarbonate, (O) ABS. From Li, L. and Chung, D.D.L. (1994) Composites, 25(3).

EP 580069, Injection molding compositions for automobile bumpers, Sumitomo Chemical Co. Ltd., Japan Toyota Jidosha Kabushiki Kaisha. 

There is not much of a difference between discoloration of the extmded and injection-molded composites made of the same materials. For the extruded samples, the AL valueis around 30 after 1000 h of weathering, while it is 28 for the... 

Choi D S, Im Y T. Prediction of shrinkage and warpage in consideration of residual stress in integrated simulation of injection molding. Composite Structures, 47,655 665(1999). 

The strength and modulus of all the conqx)sites are higher than the neat resin. The properties of the compression molded sanq)les are similar to the injection molded conqx)sites even though the injection molded composites have been exposed to high tempaature twice. The injection molded conqx)sites are darker than their conqrression molded counterparts. Also, composites with more fibers are darker, indicating that some fiber degradation has occiured. The strength of these conqx)sites eventually drops as the fiber content increases. 

Mechanical Properties and Morphology of PMMA Grafted Silica/PMMA Injection Molded Composites... 

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