JEC COMPOSITES MAGAZINE - Issue #110 - January/February 2017 - 32

AUTOMOTIVE
raw materials

A new generation of aesthetic
composites based on styrenic copolymers

PIERRE JUAN, Composite Thermoplastic
Director, DR EIKE JAHNKE, Product
Manager Transparent Specialties -
Styrenics Specialties EMEA,
PHILIPP DEITMERG, Business Development
Manager Composites, DR. MARKO BLINZLER,
Global Development Coordinator,
DR. NORBERT NIESSNER, Director Global
R&D and Intellectual Property
INEOS Styrolution

The INEOS Styrolution Research Network is a unique R&D model in the plastics
industry that goes beyond the classical funding of university projects. At the centre of this partnership is a project coordinator who evaluates new technologies
for the deployment of styrenics. The most promising findings are followed up by
a cross-functional team including researchers from both parties. This approach
constantly grows the innovation pipeline. The project presented below focused
on the evaluation of specific styrene copolymers as a lightweight, robust and
aesthetic material.

ontinuous fibre-reinforced thermoplastics are gaining growing importance
in various industries due to their lightweighting potential, high design freedom and
applicability in mass production.
Apart from their exceptional mechanical performance, however, composite thermoplastic
parts based on semi-crystalline polymer matrices (PA, PP) usually allow only for a limited surface quality. This is mainly due to the
imprint of the fibre reinforcement resulting
from shrinkage/warpage of the matrix and
"read-through" of the back-moulded structural ribs. Hence, so far, the applications of
composite thermoplastics have focused on
structural parts without any particular aesthetical value.
As part of a project with R&D partners from
academia and industry, a new generation of
high-strength fibre-reinforced composites
based on styrenic copolymers was developed.
This project focused on the evaluation of
specific styrene copolymers as a lightweight,
robust and aesthetic material. It was supported by the NMF (Neue Materialien
Fürth GmbH) and NMB (Neue Materialien
Bayreuth GmbH) research institutes, which
joined the INEOS Styrolution research network in 2013.

In a second step of the project, INEOS
Styrolution decided to validate the product
development and created a prototype mould
to evaluate the processing behaviour and the
surface quality that can be achieved with this
new material using different types of surface
decoration.
Performance of styrenic copolymer composites in semi-structural applications
The early technical evaluation of such composite thermoplastic sheets showed that specific
styrenic copolymers represented promising
new candidates as a matrix.
A modified SAN resin was developed and selected to provide a very high flow and hence
enable complete impregnation of the continuous fibres being present typically from 45%

Fig. 1: Stress
deflection curve of
StyLight* vs. PA & PC
(measured at NMF)

jec composites magazine / No110 January - February 2017

to 50% volume content. As the sizing of
commercially available glass or carbon fibres
is not designed for styrenic polymers in particular, the SAN polymer matrix was modified to be more compatible with the existing
fibre sizing.
This resulted in composite sheets based on
glass or carbon fibre fabrics featuring an
excellent mechanical performance profile
(stiffness, strength, and impact strength),
being on par with today's most advanced
(PA6 or PC based) thermoplastic composites in the market place (see Figure 1,
showing the deflection curve of a four-layer
woven glass fabric with a 45% GF volume
content in dry conditions measured on
2 mm-thick test bars).

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #110 - January/February 2017