Page 22 - Engineering Plastics Handbook

xx Preface

fabricated in some fashion, whether it is an injection-molded part, an
extruded rod, or thin coating, must be thermally cured in order for the
material to reach its maximum properties.” Polyamide-imide curing
schedules for coatings and molded parts and graphs of cure cycle vs. ten-
sile strength and cure cycle vs. flexural strength are valuable sources
for information on proper curing and the effects of cure on strength
properties.
A wide range of numerous PAI products is covered in the chapter, and
several of these are given particular attention. These include a “primer”
coating with good adhesion between metal and fluoropolymer for nonstick
cooking pans and pots; wire enamel; friction and wear-resistant, high-
speed bobbins and rotary compressor vanes; automotive transmission
components, thrust washers, seal rings, and check balls; race car sus-
pension bushings; aircraft air return valves, engine shrouds, thermal
insulating fastener return mounts, and clip nuts; agriculture and con-
struction vehicles and equipment, precision-machined poppets, and seats
and spools in fluid (hydraulic) power systems; aerospace adhesives for hon-
eycomb structures; and semiconductor test sockets. Tensile strength and
®
flexural strength of reinforced Torlon PAI at 204°C (399°F) are graphi-
cally compared with reinforced PES, PEI, PPS, and PAEK composites.
Processing conditions for injection molding and compression molding PAI
are described.
Chapter 13, “Polyarylethersulfones (PAES),” from Solvay Advanced
Polymers covers basic and advanced developments of sulfone polymers,
especially polysulfone (PSF), polyethersulfone (PES), higher perform-
ance with higher toughness polyphenylsulfone (PPSF), and, more recently,
TM
the higher temperature polyarylethersulfone Supradel HTS with a T g
of 265°C (509°F) and heat deflection temperature of 255°C (491°F). The
company did not disclose the repeat unit at the time the chapter was
TM
written. Supradel HTS notched Izod impact strength is “on a par with
that of polycarbonate” according to the authors. In addition to a compre-
hensive description of the chemistry of nucleophilic polycondensation
polymerization, the chapter clearly relates the macromolecular charac-
terizations of sulfone polymers with performance and processing proper-
ties. The authors observe that “the ether linkage that is common to the
sulfone polymers imparts chain flexibility which allows for mechanical
toughness and attractive melt rheological properties for thermoplastic fab-
rication.” The authors describe further attributes of the ether linkage, sul-
fone moieties, and many other relationships between the sulfone polymers’
characterizations and their properties. The chapter describes the unique
combination of transparency, inherent flame resistance, and low smoke
(particulate) emissions; electrical properties, ESCR (environmental
stress crack resistance), radiation resistance (x-ray, electromagnetic,
electron beam, gamma, microwave, and infrared), and solubility. Sulfone