I. INTRODUCTION

Most useful rubber articles, such as tires and mechanical goods, cannot be made without vulcanization. Unvulcanized rubber is generally not very strong, does not maintain its shape after a large deformation, and can be very sticky. In short, unvulcanized rubber can have about the same consistency as chewing gum.

The first commercial method for vulcanization has been attributed to Charles Goodyear. His process (heating natural rubber with sulfur) was first used in Springfield, Massachusetts, in 1841. Thomas Hancock used essentially the same process about a year later in England. Since those early days, there has been continued progress toward the improvement of the process and in the resulting vulcanized rubber articles. In addition to natural rubber, over the years, many synthetic rubbers have been introduced.Also, in addition to sulfur, many other substances have been introduced as components of curing (vulcanization) systems. This chapter is an overview of the science and technology of vulcanization. Emphasis is placed on the vulcanization of general-purpose high-diene rubbers (e.g., natural rubber [NR], styrene-butadiene rubber [SBR], and butadiene rubber [BR]) by sulfur in the presence of organic accelerators.

The accelerated-sulfur vulcanization of these rubbers along with the vulcanization of other rubbers which are vulcanized by closely related technology (e.g., ethylene-propylene-diene monomer rubber [EPDM], butyl rubber [IIR], halobutyl rubbers, and nitrile rubber [NBR]) comprises more than 90% of all vulcanization. Nevertheless, we give some consideration to vulcanization by the action of other vulcanization agents such...