Tham khảo tài liệu 'rubber compounding - chemistry and applications part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 3 Special-Purpose Elastomers Sudhin Datta ExxonMobil Chemical Co. Baytown Texas . I. INTRODUCTION TO SPECIALTY ELASTOMERS The worldwide production capacity for all elastomers is around 17 500 kilotons per year kt yr and is split between natural rubber and synthetic elastomers 1 . Historically the split has ranged from 40 to 50 natural rubber though the level of natural rubber being used has been decreasing due to the emergence of new solution-polymerized elastomers and specialpurpose polymers. Specialty elastomers make up a small but important portion of the arena of synthetic elastomers and consist of elastomers that have an annual estimated consumption of about 1000 kt yr or less. These elastomers occupy critical application areas principally because they have one or more unique attributes. This distinction in the attributes of the specialty elastomers compared to general-purpose rubbers GPR and the structural features responsible for this distinction are illustrated in Table 1. Morton 2 and Dick 3 compiled excellent reviews of special-purpose elastomers. The purpose of this chapter is therefore to provide a brief overview of this important class of polymers and as appropriate provide references for further reading. It is important to realize that specialty elastomers have a variety of components and structures that have been selected to provide key performance attributes. These compositions have been recognized by the ISO 1629 nomenclature procedures Table 2 and have been commonly used to distinguish them. For example the word rubber is inserted after the name of the monomers from which the rubber was prepared and is applicable to Copyright 2004 by Taylor Francis Table 1 Specialty Elastomers Estimated Volumes in 2001 and Key Attributes Elastomera Key attribute Structural feature Estimated volume kt yr EPM EPDM Environmental resistance Saturated backbone 1200 Plastomer Environmental resistance compatibility with iPP Saturated backbone higher a-olefin .
