POLYM, description

Figure 10. IsotachopherogrMS of poly(styrenesulfonate) Na salt of different molecul u weights. Polymer descriptions in TaJsle IV.

The reader must be aware of some details regarding the brief polymer description in Table 1.5 (columns 2 and... 

The EPA refers to a polymers description for Inventory purposes as its chemical identity In practice the chemical identity can be very different from the polymer s chemical composition, and so this term is confusing and misleading and will not be used here. 

Prior to the EPA s clarification, there had been different interpretations of whether free radical initiators must be listed in the Inventory description for polymers. As a result, the EPA had to adopt a poUcy to prevent unfair burdens on people who had consulted the Inventory prior to the June 28, 1989 clarification. In the clarification, the EPA stated that all polymers that were put on the Inventory or were the subject of a Notice of Commencement filed on before June 28,1989 can be made with any amount of free radical initiator, whether or not the free radical initiator is part of the polymer description on the Inventory. Of course, if the free radical initiator is Usted in the Inventory representation of the polymer, that free radical initiator must be used, but it may be in any amount. 

Polymer Description. A lattice model heteropolymer (129-131) provides a simple yet instructive description of a protein molecule. In general, the coarse graining is such that each segment represents a portion of the protein (ie many amino acids). In the simplest case, two t3q>es of segments are present these may be thought of as polar and hydrophobic (132-138). In other cases, a distribution... 

Clearly, nucleic acids are also amenable to a polymer description. Theoretical (176) and simulation (177,178) methods have been used to determine the strnctnre, dynamics, and thermodynamics of nucleic acid chains on surfaces. 

Moreover, one should distinguish for a polymer description between o(sigma) - bonds localized and immobile forming the covalent bonds between atoms of carbon inside the chain and those 2t(pi)-conjugate double bonds of those electrons being also partly localized yet not so tight as the o-electrons. 

ASTM designations (D418) by chemical polymer description are used in the following table yet within each class the properties can vary widely, depending on the exact composition, heat treatment, service temperature, and apphcation. Typical uses, such as rubber springs and cushioning, permit an almost unhmited number of combinations of design variables. 

---