Composites impact properties

Most of the polymer s characteristics stem from its molecular stmcture, which like POE, promotes solubiUty in a variety of solvents in addition to water. It exhibits Newtonian rheology and is mechanically stable relative to other thermoplastics. It also forms miscible blends with a variety of other polymers. The water solubiUty and hot meltable characteristics promote adhesion in a number of appHcations. PEOX has been observed to promote adhesion comparable with PVP and PVA on aluminum foil, cellophane, nylon, poly(methyl methacrylate), and poly(ethylene terephthalate), and in composite systems improved tensile strength and Izod impact properties have been noted. 

There are several ways in which the impact properties of plastics can be improved if the material selected does not have sufficient impact strength. One method is by altering the composition of the material so that it is no longer a glassy plastic at the operating temperature of the product (Chapter 6). In the case of PVC this is done by the addition of an impact modifier which can be a compatible plastic such as an acrylic or a nitrile rubber. The addition of such a material lowers the glass transition temperature and the material becomes a rubbery viscoelastic plastic with much improved impact properties. This is one of the methods in which PVC materials are made to exhibit superior impact properties. 

Another successful development was based on morphological studies of traditional impact-resistant polystyrenes. Products with unusually big particles and a certain combination of composition and properties are particularly resistant to stress cracking (84). They have achieved considerable success on the... 

Kang, T.J. and Lee, S.H, (1994). Effect of stitching on the mechanical and impact properties of woven laminate composites. J. Composite Mater. 28, 1574-1587. 

The high impact strength thermoplastic resin exhibits different characteristics. According to the rubber used in the composition, the properties of the final product can be tailored to some extent. 

The impact properties of an injection-molded blend of PP and EPDM are sensitive to blend composition, processing variables, and test conditions. At all temperatures tested, the impact strength of blends of PP with up to 30% EPDM increase with EPDM content and decrease with test temperature. The temperature dependence of the impact strength increased with the fraction of EPDM. The impact strength appears to... 

PVC can be chlorinated (CPVC) and be alloyed with other polymers like ABS, acrylics, polyurethanes, and nitrile rubbers to improve its impact resistance, heat deflection, and processability. Although these vinyls differ in having literally thousands of varying compositions and properties, there are certain general characteristics that are common to nearly all these plastics. Most materials based on vinyls are inherently TP and heat sealable. The exceptions are the products that have been purposely compounded with TSs or crosslinking agents are used. 

Work undergone in this area has looked at tensile and impact properties of a PVC composite filled with hollow glass beads, of three different sizes, and different volume fractions (96). The influence of particle shape and silane coupling agents, for surface treatment of glass beads, on mechanical properties has also been investigated (116, 366). 

Maero molecular Materials and Engineering 287, No.9, 11th Oct.2002, p.588-91 TENSILE AND IMPACT PROPERTIES OF HOLLOW GLASS BEAD FILLED PVC COMPOSITES Ji-Zhao Liang... 

Impact Failure. Standard notched Izod impact measurements have been made over wide temperature ranges on specimens cut from compression molded %-inch thick sheets of BPA polycarbonate and two BPA carbonate-silicone block polymers (Figure 4) (see Table I for compositions and properties). In the homopolymer a ductile-brittle transition occurs at 0° to —15°C, as reported previously (4, 5). Introduction of 15 and 25% silicone lowers the transition to —45° and —110°C (block polymers A and B). As indicated in Table I, this increase in toughness at low temperature is accompanied by the reduction of modulus and yield stress. 

Numerous studies have been made of the mechanical properties of fibrous composites these include recently published papers on impact properties by Izod (1,2, 3,4) and Charpy (5,6) and drop weight (7) tests. We reported the Charpy impact fracture behavior of various glass-polyester composites regarding the effects of temperature (8,9,10), specimen size (8), and fiber orientation (10). This paper describes the effects of the tough-brittle transition in the impact behavior of glass-polyester composites which occurs with a variation of temperature and specimen size. 

Results of the forging study on the selected 4640 composition have shown that PM forgings were competitive with wrought materials from a property standpoint. Tensile and yield strength were density dependent and comparable to wrought materials in the range of 98 per cent or higher density. Ductility and impact properties were very sensitive to minor amounts of residual porosity... 

Table in also shows the effect of BG content on the properties of injection-molded BDft/BG/BD polyesters. The two copolyesters which contained 65 and 73 mol % BG and did not solidify during preparation were molded in their anisotropic state (Ti s above molding temperatures), and it is significant that these two ICP s have the highest tensile, flexural, and impact properties (and the highest HOT s at 264 psi stress). The other four compositions in the table became solid or semi solid during preparation at 300°C, and additional molecular weic t buildup was achieved by solid-state polymerization to give I.V. s comparable to... 

There are many icy bodies in addition to comets in the solar system they are icy satellites and Kuiper belt objects. Icy satellites of the Jupiter and Saturn systems were observed by spacecraft to clarify their densities and surface compositions. As a result, it is widely accepted that the main component of icy satellites is water ice, and the existence of water ice is confirmed by the observation of near infrared reflectance spectra. Icy satellites were revealed to have various surface morphologies and geologic activities depending on their origin and the thermal evolution process. Most of the icy satellites have densities from 1 to 2 g/cm which means that these bodies are a mixture of ices and silicates. Icy satellites were formed by collisional accretion of small porous bodies. These bodies could be ice-silicate mixture and the porosity was corrupted according to their growth. Therefore, impact properties of an ice-silicate mixture with various porosities are necessary to be clarified in order to study the formation process of icy satellites. I review systematic experimental results on impact of ice-silicate mixture in Section 3. 

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