Page 213 - Engineering Plastics Handbook

186 Engineering Plastics

Modified PPE resins are available as unfilled and reinforced grades, as
well as grades formulated with and without flame-retardant additives.
Moreover, modified PPE can be opaque or transparent, rigid or flexible.
In addition, modified PPE offers a broad range of processing options includ-
ing injection molding, extrusion, blow molding, expanded foam, and struc-
tural foam molding. PPE is used in blends with polystyrene, alloys with
polyamide and polypropylene, and thermoset resins. Clearly the PPE-
based resins offer one of the most versatile product families.
The versatility of modified PPE resins has resulted in an extensive vari-
ety of applications which include automotive interior, exterior, and under-
the-hood applications; computer and business equipment; electrical and
electronic devices; health care; building and construction; telecommuni-
cations; appliances; water handling equipment; and microwavable food
packaging. Noryl modified PPE resins have become the world’s most suc-
cessful and best-known polymer blends and alloys.
Representative grades are discussed in this chapter to show the scope
and breadth of PPE-based grades available, and it is not intended to be
an inclusive list.
Properties listed in this chapter are determined on standard test parts,
using recommended molding conditions, and evaluated by using standard
test methods. These data are intended for comparative purposes only and
are not intended to give an indication of a material’s ability to perform
under various conditions. Indeed, plastic parts in end-use situations can
encounter mechanical stress, impact, flexure, elevated temperatures, dif-
ferent environments, etc. Proper part design and correct molding condi-
tions are equally important as resin grade selection for an application. It
is of importance to minimize stresses in the part through both design and
processing.
Abbreviations are used to describe some physical properties in this
chapter:
RTI Relative thermal index (formerly named continuous-use tem-
perature) is the maximum service temperature at which the critical
properties of a material will remain within acceptable limits over a
long time, as established by UL 746B. There can be up to three inde-
pendent RTI ratings assigned to a material:
■ RTI Electrical By measuring dielectric strength.
■ RTI with Impact By measuring tensile impact strength.
■ RTI without Impact By measuring tensile strength.
Vicat Vicat softening temperature (ASTM D 152) is the temperature
at which a plastic starts to soften rapidly. There are two methods:
■ Vicat A It has a load of 2.25 lb (10 N).
■ Vicat B It has a load of 11.24 lb (50 N).
HDT Heat deflection temperature (ASTM D 648) is a relative meas-
ure of a material’s ability to perform for a short time at elevated