Philosophy of Polymer Compounds

Compounds are pervasive in the polymer industry. Indeed, even presumably neat polymers are compounds containing antidegradents, which are antioxidants and/or anti-ozonants. These additives are small polar molecules. In more complex compounds there are in addition other polymers, reinforcing fillers, oils, curatives, and accelerators, which are intended to crosslink polymers. These are also small, usually polar, molecules. This chapter is about the philosophy of the polymer compound and the characteristics of their various ingredients. 

Generally, neat polymers are not adequate for the applications intended for customer use. This inadequacy is usually associated with insufficient chemical resistance against attacks of oxygen, ozone, and heat. They may also possess insufficient modulus, hardness, or toughness. Another common problem is insufficient creep resistance in the basic polymer. 

Polymers need to be modified to meet the customer s requirements. There are various ways to improve the polymer properties to accomplish this the blending of two or more polymers, the addition of various fillers, or the inclusion of antidegradation agents. Each polymer, filler, or other additive has a different chemical structure. 

The relative amounts and nature of these ingredients depend upon the desired application. The fillers and reinforcing particles increase modulus and tensile strength as well as reducing cost. The oils and plasticizers reduce these same mechanical properties but introduce flexibility. The processing aids improve the extrusion and moldability of the compounds. Curatives and curative accelerators allow for the efficient crosslinking of polymer systems, which prevent creep and cold flow. 

In this chapter we will discuss the nature and structure of the individual ingredients in polymer compounds, including polymer, fillers, oils/plasticizers, antidegradents, curatives, and accelerators. The manner in which these substances interact with each other and boundaries will be the subject of the succeeding chapters. 

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