Molded polymers

Another example of static SIMS used in a more quantitative role is in the analysis of extmded polymer blends. The morphology of blended polymers processed by extrusion or molding can be affected by the melt temperature, and pressure, etc. The surface morphology can have an effect on the properties of the molded polymer. Adhesion, mechanical properties, and physical appearance are just a few properties affected by processing conditions. 

In a molded polymer blend, the surface morphology results from variations in composition between the surface and the bulk. Static SIMS was used to semiquan-titatively provide information on the surface chemistry on a polycarbonate (PC)/polybutylene terephthalate (PBT) blend. Samples of pure PC, pure PBT, and PC/PBT blends of known composition were prepared and analyzed using static SIMS. Fn ment peaks characteristic of the PC and PBT materials were identified. By measuring the SIMS intensities of these characteristic peaks from the PC/PBT blends, a typical working curve between secondary ion intensity and polymer blend composition was determined. A static SIMS analysis of the extruded surface of a blended polymer was performed. The peak intensities could then be compared with the known samples in the working curve to provide information about the relative amounts of PC and PBT on the actual surface. 

Its main field of application is in plastics. 1/3 SD HDPE samples, both transparent and opaque, withstand exposure to 300°C for 5 minutes, while 1/25 SD specimens are heat stable up to 250°C. Temperatures in excess of this value shift the shade towards more yellowish hues. P.O.64 does not have a nucleating effect on its medium, i.e., it does not affect the shrinkage of partially crystalline injection-molded polymers. 

Elemental Analysis. A Phillips PW 1410/70 X-ray fluorescence spectrometer with Cr radiation was used to measure the relative quantities of Br in the molded polymer samples. Extractable bromide and chloride ions were detected with specific ion electrodes after a 48-hour, 120 C steam bomb extraction. 

Figure 6.104 Variation in birefringence of injection molded polymer of width H. Adapted from P. C. Powell and A. J. Ingen Housz, Engineering with Polymers, p. 314. Copyright 1998 by P. C. Powell and A. 1. Ingen Housz.

Refractive Index Measurements. Refractive indices were measured at 23 °C on molded polymer sheets, using an Abbe type refractometer. Suitable contact liquids were employed as required. 

Typical mechanical properties for transparent injection-molded polymers, designated MBAS, having a compositional range of from 11-18%, 1,3-butadiene, 34-39% styrene, and 23-25% each of acrylonitrile and methyl methacrylate are given in Table IV. This polymer is closely akin to the polyblend described previously, differing by containing a butadiene-styrene elastomer backbone, with a terpolymer resin graft consist-... 

Amon M, Denson C (1986) A study of the dynamics of foam growth Simplified analysis and experimental results of bulk density in structural foam molding. Polymer Eng Sci 26 255-267 Azbel IY, Tolstikhin IN (1990) Geodynamics, magmatism, and degassing of the Earth. Geochim Cosmochim Acta 54 139-154... 

Dumitrescu OR, Baker DC, Foster GM, Evans KE. Near infrared spectroscopy for in-line monitoring during injection molding. Polymer Testing 2005, 24, 367-375. 

As mentioned, polymer hybrids based on POs are effective as a compati-bilizer between the olefinic materials and polar ones. Furthermore, some polymer hybrids, such as PP-g-PMMA, etc., show good mechanical strength as polymer materials. On the other hand, surface modification of the molded polymer is one of the most attractive methods to let polyolefin materials functionalize. In this sense, surface polymerization of functional monomers on polyolefins is an important subject for polyolefin hybrids. As previously referred to, the growth of PS on PP via the RAFT process has been reported [92]. 

L. R. Schmidt, A Special Mold and Tracer Technique for Studying Shear and Extensional Flows in a Mold Cavity during Injection Molding, Polym. Eng. Sci., 14, 797 (1974). 

Fig. 14.26 Diameter (SD, thickness (S7), and weight (Sw) swell of a parison extrudate from a commercial blow-molding machine equipped with CCD camera equipment and parison pinch-off mold based on the design of Shepak and Beyer (69). (a) A chain extended multibranched polyamide-6 resin (b) the former with 12% glass fiber of 10 pm diameter 60 1 L/D and (c) polyolefin modified polyamide-6 with some carbon black. [Reprinted by permission from A. H. Wagner and D. Kalyon, Parison Formation and Inflation Behavior pf Polyamide-6 During Extrusion Blow Molding, Polym. Eng. Sci., 36, 1897-1906 (1996).]...

M. R. Kamal, V. Tan, and D. Kalyon, Measurement and Calculation of Parison Dimensions and Bottle Thickness Distribution during Blow Molding, Polym. Eng. Sci., 21, 331-338 (1981). 

Polymethylsiloxanes can also be obtained by the hydrolytic copolycondensation of methylchlorosilanes of various functionality. Thus, by the hydrolytic copolycondensation of methyltrichlorosilane and dimethyldichlo-rosilane one can obtain thermosetting polymethylsiloxane, which quickly solidifies at a relatively low temperature (approximately 150 °C) without any catalysts. It is used as a binding agent in pressure compositions, as well as as a 5% petrol solution to treat the surface of metal pressure molds to facilitate their splitting when molding polymer materials. 

The experimental results with molded polymer samples show that the mechanical energy efficiency. in melting solid polymers by... 

Microscopy. Three levels of magnification were required to characterize adequately the morphology of the molded polymer samples and of fracture surfaces after the impact test. A low power binocular microscope covering the magnification range from 2 to 12 times permitted initial evaluation of the fracture surface after which specific areas and... 

MEASUREMENT OF RESIDUAL STRESSES IN INJECTION-MOLDED POLYMER PARTS BY TIME-RESOLVED FLUORESCENCE... 

Reaction Injection Molding. Molded polymer samples were produced in our laboratory-size RIM machine (9). Details of reactant preparation and molding procedures are found elsewhere (9-10). Briefly, the polyol and extender are blended as received at the desired stochiometry. Catalyst is added when required and the mixture... 

Kubat, J. Manson, J.A. High Modulus/high strength polyethylene obtained by high pressure injection molding. Polym. Eng. Sci. 1983, 23 (16), 869. 

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