Plasticizers general characteristics

Q Predict the general characteristics of a polymer based on its structure, cross-linking, and presence of plasticizers. Explain how its characteristics change as the polymer is heated. 

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. 

Rotary kiln processes are continuous processes that use a rotary kiln reactor to depoly-merize plastic [4, 5]. They have a lower capital cost compared with fluidized-bed processes and their liquid product resembles crude oil. The following are some general characteristics of kiln processes ... 

Table 5 General characteristics of epoxy-based carbon fiber reinforced plastics (CFRPs)...

Two chapters in the second section contain descriptions of specific commercially available polymers that perform under demanding conditions. Another chapter describes several high-performance plastics and gives general characteristics for each. The final chapter in this section is a comprehensive review of attempts to make polymers that fight back against attack by bioorganisms. 

The thermoset plastics generally have superior abrasion and dimensional stability characteristics compared with the thermoplastics, which have better flexural and impact properties. In contrast to the thermoplastics, thermosetting polymers, as the name implies, are changed irreversibly from fusible, soluble products into highly intractable cross-linked resins that cannot be molded by flow and so must be fabricated during the cross-linking process. Typical examples are ... 

Plastics generally consist of macromolecules called polymers and additives which are used to modify the properties of the material polymers rarely consist of pure polymer. Additives are used in the production of plastics to enhance the appearance, improve strength and change certain characteristics. Plastics continue to advance into... 

The rubber extrusion technology appears to be considerably behind the plastics extrusion technology. Kennaway, in one of the few articles on rubber extrusion [8], attributes this situation to two factors. The first is the frequent tendency of rubber process personnel to solve extrusion problems by changing the formulation of the compound. The second is the widespread notion that the extrusion behavior of rubbers is substantially different from plastics, because rubbers crosslink and plastics generally do not. This is a misconception, however, because the extrusion characteristics of rubber and plastics are actually not substantially different [9]. 

Thermo set polyesters are typical of the thermoset plastics—the characteristics of which are good temperature resistance, good tensile strength and stiffness, a high degree of hardness, low impact strength unmodified, low extensibility, and generally superior resistance to creep and cold flow. Properties of some typical materials are shown in Table 1-4. 

Nonreinforced plastics generally have much higher coefficients of linear thermal expansion (CLTE) than conventional metal, wood, concrete, and other materials. CLTEs also vary significantly with temperature changes. There are RPs that do not have these characteristics. With certain types and forms of fillers, such as graphite, RPs can eliminate CLTE or actually shrink when the temperature increases. 

NF T51-108 December 1984 Plastics. Friction and wear by sUding. Definitions of terms and general characteristics. 

NB. only GENERAL CHARACTERISTICS CAN BE COVERED (N THESE CHARTS. MOOlFtCATlONS OF EACH MATERIAL t G. THE TYPES OF NYLON CAN CHANGE THE PERFORMANCE CHARACTERISTICS OF THE PLASTICS... 

Table 3. General Characteristics of Commonly Used PVC Plasticizers. 

Titanium dioxide pigment coated with pentaerythritol, trimethylolpropane, or trim ethyl ol eth an e exhibits improved dispersion characteristics when used in paint or plastics formulations. The polyol is generally added at levels of 0.1—0.5% (96). 

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