Plastic impact-resistant

Lenses for safety glasses are made from highly impact resistant plastics such as modified acrylics and polycarbonate. They will resist puncture from flying objects and offer the exceptional eye protection. They can be molded to prescription requirements. 

Based on castor oil derived elastomers and crosslinked polystyrene, a simultaneous mode of polymerization can be successfully employed to synthesize prototype engineering materials such as tough, impact resistant plastics and reinforced elastomers. 

The SIN s from castor oil and the other oils were tough materials, either reinforced elastomers or impact resistant plastics depending on their composition and whether phase inversion had occurred. Impact strengths in the range of 40-60 J/m were obtained. The glass transitions of the rubber phase of the SIN s tended to be a little higher than those shown in Table IV. The polystyrene phase... 

B. Vollmert, Impact-resistant plastic compositions comprising a styrene polymer and a cross-linked acrylic acid ester polymer, and process for preparing same, US Patent 3 055 859, assigned to BASF AG, September 25,1962. 

Their non-linear and often synergistic mechanical behavior which arises from their above mentioned multiphase morphology. Thus, both impact resistant plastics and thermoplastic elastomers have been bom. 

When one polymer of an IPN was plastic and the other was rubber, the combination showed synergistic properties reinforced rubbers, impact resistant plastics, or noise damping materials were reported. Because of the macroscopic network structure formed in IPN s, they are thermoset and cannot be molded. However IPN s have been made by emulsion polymerization so that each individual emulsion particle is an IPN in miniature form containing both networks (75, 76, 77, 78, 82, 83). Emulsion polymerization allows the molding of IPN s if the crosslink density of the miniature IPN s is not too high. 

Inhalation containers are made of glass, plastic, or metal or a combination of these materials. Glass containers are precisely engineered to provide the maximum pressure safety and impact resistance. Plastics may be used to coat glass containers for improved safety characteristics, or to coat metal containers to improve corrosion resistance and enhance the stability of the formulation. Metals used as containers include stainless steel, aluminum, and tin-plate steel. It is also important that containers should be tested to ensure that extractables or leachables and particulates on the internal surfaces of containers are controlled. 

Plasticizers are added to thermoplastic compounds to improve flexibility, increase the acceptance level for inorganic additives, and to aid in processing, such as melt flow reduction. Synergistic effects can also be obtained such as reduction of shear during mixing and improved impact resistance. Plasticizer compounds typically include phthalates, adipates, esters, and fatty acid esters (oleates, palmitates, stearates). 

With large amounts (> 80%) of /3-pinene in the chain tough, impact resistant plastics may be anticipated. 

Another advantage of using IPNs involves its thermosetting characteristics. By definition, IPNs will not flow when heated. A partial exception is the thermoplastic IPNs, which behave crosslinked at ambient temperatures, but flow at elevated temperatures. While some IPNs are tough, impact-resistant plastics, the crosslinking permits many other types of applications, such as sound and vibration damping, biomedical, adhesives and coatings uses, etc. (see Section 6.5). 

Lexan is a clear, transparent, strong, and impact-resistant plastic with literally countless applications. It is used in both protective and everyday eyeglasses as illustrated in Figure 27.10. The Apollo 11 astronauts wore Lexan helmets with Lexan visors on their 1969 trip to the moon. CDs and DVDs are Lexan polycarbonate, as are many cell phones, automobile dashpanels, and headlight and taillight lenses. 

Polymer blends containing one plastic phase and one rubbery phase will be emphasized in the next eight chapters. Depending on which phase predominates, such combinations yield impact-resistant plastics or reinforced elastomers. The briefer development of rubber-rubber blends given here belies the importance of the subject, since some 75% by volume of all rubber used is in blends. Also treated briefly are the plastic-plastic grafts, the best known of which are the castable polyesters. 

An important result of such studies was the realization that almost all commercially important polymer blends, blocks, and grafts clearly exhibit phase separation, and that each has its own characteristic fine structure. An example of a typical morphology for an impact-resistant plastic is shown in Figure 2.4. Although the polymer contains only 6% rubber, much of the volume of polystyrene is occluded (Wagner and Robeson, 1970). Those interested in the details of electron microscope construction and operation, as well as experimental techniques, should consult Hall (1966) or Kay (1965). 

With both the PEA/P(S-co-MMA) and PB/PS IPN s, an important variable is the ratio of elastomer to plastic in the final material. When the plastic component predominates, a type of impact-resistant plastic results. In this manner the PB/PS IPN s are analogous to the impact-resistant graft copolymers. When the elastomer component predominates, a self-reinforced elastomer results, the behavior resembling that of the ABA-type block copolymers (thermoplastic elastomers) described in Section 4.4. When the overall compositions of both the PB/PS and the PEA/P(S-co-MMA) series are close to 50/50, the materials behave like leathers. 

Both the modulus-temperature relationships presented in the preceding sections and the tensile data presented above are strikingly similar to those demonstrated for other rubber-plastic combinations, such as the thermoplastic elastomers (see Chapter 4 and the model system presented in Section 10.13) and the impact-resistant plastics (Chapter 3). The IPN s constitute another example of the simple requirement of needing only a hard or plastic phase sufficiently finely dispersed in an elastomer to yield significant reinforcement. Direct covalent chemical bonds between the phases are few in number in both the model system (Section 10.13) and present IPN materials. Also, as indicated in Chapter 10, finely divided carbon black and silicas greatly toughen elastomers, sometimes without the development of many covalent bonds between the polymer and the filler. 

Cross-linked networks can include bulk materials, hydro-gels, and thin lilms with applications ranging from impact-resistant plastics to biomaterials, and lithographic aids. ° Traditional aoss-linked systems have... 

Cellulose nitrate (CN) or nitrocellulose is a nitric acid ester of cellulose manufactured by the action of a mixture of sulfuric acid and nitric acid on cellulose, such as purified cotton linters. The major use of plastics-grade cellulose nitrate is in the coating field. Despite its disadvantages of flammability, instability, and poor weathering properties, cellulose nitrate is one of the cheapest and most highly impact-resistant plastic. It still has many uses because of these properties, including fountain pens, tool and brush handles, eyeglass frames, and some motion picture film. It accounts for only a small fraction of the volume of cellulose plastics. Cellulose nitrate materials are sometimes simply called nitrates. 

An important example of a polymer is that of polyvinylchloride, shown in Figure 9.15. This polymer is synthesized in large quantities for the manufacture of water and sewer pipe, water-repellant liners, and other plastic materials. Other major polymers include polyethylene (plastic bags and milk cartons), polypropylene (impact-resistant plastics and indoor-outdoor carpeting), polyacrylonitrile (Orion and carpets), polystyrene (foam insulation), and polytetrafluoroethylene (Teflon coatings and bearings) the monomers from which these substances are made are shown in Figure 9.16. 

As per the definition of patentability, each patent addressed a novel method of synthesis, process, or application. Table summarizes some 21 selected patents based on chemical crosslinking. Applications range from ion exchange resins, through adhesives, to impact-resistant plastics. 

Ion exchange resin Impact-resistant plastic Adhesive... 

Impact-resistant plastic Impact-resistant plastic... 

N. Devia, J. A. Manson, and L. H. Sperling, Simultaneous Interpenetrating Networks Based on Castor Oil Elastomers and Polystyrene. IV. Stress-Strain and Impact Loading Behavior, Polym. Eng. Sci. 19(12), 878 (1979). Castor oil-polyester/PS SINs. Mechanical behavior. Impact resistant plastics. 

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