Fibers, polymer classification

Examples of Commercial Blends. In this subsection we will review some of the commercial activity in polymer blends. We find it interesting and informative to categorize examples into specific areas that relate to both technical issues associated with these mixtures, such as miscibility or crystallinity, and the intended commercial applications, such as rubbers or fibers. Other schemes of classification could be used, and the present one is not intended to be exhaustive. Likewise, there is no intent to mention all of the commercially interesting polymer blends, but rather, the present purpose is to illustrate some of the possibilities. Information about the examples used here was obtained from product literature supplied by the companies who sell these blends and from various literature references that have attempted to review commercial developments in polymer blends (70-76). 

This review is intended to focus on ceramic matrix composite materials. However, the creep models which exist and which will be discussed are generic in the sense that they can apply to materials with polymer, metal or ceramic matrices. Only a case-by-case distinction between linear and nonlinear behavior separates the materials into classes of response. The temperature-dependent issue of whether the fibers creep or do not creep permits further classification. Therefore, in the review of the models, it is more attractive to use a classification scheme which accords with the nature of the material response rather than one which identifies the materials per se. Thus, this review could apply to polymer, metal or ceramic matrix materials equally well. 

The most fundamental classification of polymers is whether they are naturally occurring or synthetic. Common natural polymers (often referred to as biopolymers) include macromolecules such as polysaccharides e.g., starches, sugars, cellulose, gums, etc.), proteins e.g., enzymes), fibers e.g., wool, silk, cotton), polyisoprenes e.g., natural rubber), and nucleic acids e.g., RNA, DNA). The synthesis of biodegradable polymers from natural biopolymer sources is an area of increasing interest, due to dwindling world petroleum supplies and disposal concerns. 

Polymers can be classified in many ways, such as by source, method of synthesis, structural shape, thermal processing behavior, and end use of polymers. Some of these classifications have already been considered in earlier sections. Thus, polymers have been classified as natural and synthetic according to source, as condensation and addition (or step and chain) according to the method of synthesis or polymerization mechanism, and as linear, branched, and network according to the structural shape of polymer molecules. According to the thermal processing behavior, polymers are classified as thermoplastics and thermosets, while according to the end use it is convenient to classify polymers as plastics, fibers, and elastomers (Rudin, 1982). 

Classification of composites by the phase inclusion size bears a philosophical aspect how small should a component in the matrix be not to make the term composite material so universal as to include in fact all materials Interatomic distances in molecules and crystals are of 1.5 10 m dimensionality, distances between iterative elements of the crystalline structure are 10 —10 m, while the size of the smallest intermolecular voids in polymers is 10 m. Note that mean nanoparticle size (plastic pigments are 10-8-10 m in size, the diameter of monocrystalline fibers or whiskers is 10 —10 m, glass microspheres are 10 —10 m) is commensurate with parameters of monolithic simple materials. This means that in the totality of engineering materials, nanocomposites occupy a place at the boundary between composite and simple materials. 

Further classification of polymers in the groups of additional polymers and condensation polymers has been on monomer composition, because this provides an orderly approach, whereas classification based on polymer uses, such as plastics, elastomers, fibers, coatings, etc. would result in too much overlap. For example, polyamides are used not only as synthetic fibers but also as thermoplastics molding compounds and polypropylene, which is used as a thermoplastic molding compound has also found uses as a fiber-forming material. 

A polymer normally used as a fiber may make a perfectly good plastic if no attempt is made to draw it into a filament. Similarly, a plastic, if used at a temperature above its glass transition and suitably cross-linked, may make a perfectly acceptable elastomer. In the following text, a brief account of some of the more common plastics, fibers, and elastomers is given. The classification is based essentially on their major technological application under standard working conditions. 

This book chapter evaluates the definition, classification, and scope of POCs in different applications. POCs represent one of the most widely used polymeric materials. Synergistic reactions between the polymer matrix and filler materials (particulate, fiber, and structural fillers) result in modified properties. This book chapter contributes a brief introduction followed by a definition of processing and an extensive illustration of the different applications of POCs in a variety of fields (consumer, medical, agricultural, packaging, transportation, electrical, construction, and textile). POCs with natural wood fiber are widely used in consumer applications. They result in wood-like texture and properties with the cost of plastic. 

Synonyms Atactic polypropylene Isotactic polypropylene Polypropene PP Propathene 1-Propene, homopolymer Propene polymer Propene polymers Propylene polymer Syndiotactic polypropylene Classification Thermoplastic polymer Definition Polymer of propylene monomers three forms isotactic (fiber-forming), syndiotactic, atactic (amorphous)... 

Classification Polymer aliphatic organic compd. Definition Water-sol. synthetic thermoplastic avail, as cast film, fiber or aq. sol n. film is characterized by oil resist., toughness, and high tens. str. Empirical (C2H40)x... 

Pyrrolidone, 1-ethenyl polymer with 1-triacontane. See Tricontanyl PVP Pyrrolidone, N-octyl-. SeeCaprylyl pyrrolidone (N-Pyrrolidonepropyl) methylsiloxane-dimethylsiloxane copolymer CAS 179005-02-8 179005-03-9 Synonyms Siloxanes and silicones, dimethyl, 3-[4-[[[3-(dimethylamino) propyl] amino] carbonyl]-2-oxo-1-pyrrolidinyl] propyl methyl Classification Polar silicone Uses Emulsifier surfactant antifoam wetting agent lubricant for fiber-plastic contact antifog for optical applies. 

Nanocomposites consist of a nanometer-scale phase in combination with another phase. While this section focuses on polymer nanocomposites, it is worth noting that other important materials can also be classed as nanocomposites—super-alloy turbine blades, for instance, and many sandwich structures in microelectronics. Dimensionality is one of the most basic classifications of a (nano)composite (Fig. 6.1). A nanoparticle-reinforced system exemplifies a zero-dimensional nanocomposite, while macroscopic particles produce a traditional filled polymer. Nanoflbers or nanowhiskers in a matrix constitute a one-dimensional nanocomposite, while large fibers give us the usual fiber composites. The two-dimensional case is based on individual layers of nanoscopic thickness embedded in a matrix, with larger layers giving rise to conventional flake-filled composites. Finally, an interpenetrating network is an example of a three-dimensional nanocomposite, while co-continuous polymer blends serve as an example of a macroscale counterpart. 

Lignocellulosic polymer composites refer to the engineering materials in which polymers (procured from natural/petroleum resources) serve as the matrix while the lignocellulosic fibers act as the reinforcement to provide the desired characteristics in the resulting composite material. Polymer composites are primarily classified into two types (a) fiber-reinforced polymer composites and (b) particle-reinforced polymer composites. Figure 1.5 (a) shows the classification of polymer composites depending upon the type of reinforcement. 

Polymer composites are also classified into renewable/nonrenewable polymer composites depending upon the nature of the polymer/matrix [1, 13, 16]. Figure 1.5 (b) show the classification of polymer composites depending upon the renewable/nonrenewable nature. Polymer composites in which both components are obtained from biorenewable resources are referred to as 100% renewable composites, while composites in which at least one component is from a biorenewable resource are referred to as partly renewable polymer composites 1, 13, 16]. Chapter 4 of the book presents a review on the state-of-the-art of partly renewable polymer composites with a particular focus on the hybrid vegetable/glass fiber composites. This chapter summarizes the hybridization effect on the properties of the final thermoplastic and thermoset polymer matrices... 

Classification of Polymer Composites Reinforced with Natural Fibers... 

Polymers can also be classified in other ways for example, many varieties of rubber are often referred to as elastomers. Dacron is a fiber, and poly(vinyl acetate) is an adhesive. The addition and condensation classifications are used in this essay. 

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