Page 214 - Engineering Plastics Handbook

Polyphenylene Ether (PPE) Blends and Alloys 187

temperatures while supporting a load. There are typically two spec-
ified loads—64 psi (0.45 MPa) and 264 psi (1.82 MPa).
NI Notched Izod impact strength (ASTM D 256). NI can be meas-
ured at various temperatures.
UNI Unnotched Izod impact strength (ASTM D 481). UNI can be
measured at various temperatures.
CTE Coefficient of thermal expansion is a measure of how much a
material will lengthen when heated (or shorten during cooling) versus
its original length with respect to the temperature range under which
the material is tested as measured. CTE values typically take into
account the direction in which the resin flowed during molding and
are reported as follows:
■ CTE, flow Measured in flow direction.
■ CTE, xflow Measured in the crossflow direction.

Inst. Impact E @ Peak Instrumented impact energy at peak (ASTM
D 3763) of a specimen is measured by dropping a load with a certain
velocity onto a specimen plaque.
UL-94 V-0, UL-94 V-1, UL-94 V-2, UL-94 5V, UL-94 HB Flame
class ratings following UL Bulletin 94. Typically the (minimum)
sample thickness which is sufficient to pass the test is reported.
Flammability ratings listed in this chapter are not intended to
reflect hazards presented by these or other materials under actual
fire conditions.

Typical Modified PPE Grades
Key properties are listed below for representative grades based on
PPE/PS blends.
Standard grades. Unfilled, general-purpose, and automotive grades offer
a broad choice of performance properties that have a range of heat resist-
ance, mechanical properties, and flow characteristics. The combination of
low specific gravity, hydrolytic stability, chemical resistance, and electri-
cal properties helps make these resins an outstanding value in a wide
range of applications. These versatile resins are used in demanding appli-
cations such as connectors, modules, mirror housings, and speakers and
trim for the automotive market. Other common markets and applications
include cellular phones and valve and pump components. In addition,
NSF and FDAcompliance grades are available. Representative properties
of standard PPE/PS grades appear in Table 9.1. Standard grades and
their key features include these:
PX0844: 235°F (113°C) HDT at 264 psi (1.82 MPa)
PX0888: 262°F (128°C) HDT at 264 psi (1.82 MPa)