Chemical Engineering August 2018 - 51

Material
PTFE
PFA
FEP
ETFE
ECTFE
PVDF
* ASTM D648
Injection molded components.
Piping systems and flexible tubing
are usually created via profile extrusion
but injection molding is another
method to create components in
specialized shapes and dimensions.
From pumps, nozzles, and valves,
PVDF components can be mass injection
molded (Figure 8). Recently,
PVDF components are being molded
for conveyor belting
for food-processing
facilities.
Traditional materials used in plastic
modular belting have faced
scrutiny recently due to plastic bits
contaminating food [9]. With PVDF,
the higher mechanical and abrasion
resistance combined with outstanding
chemical resistance have proven
to be a longer-lasting solution. Both
rigid and copolymer grades of PVDF
can be molded into a variety of parts.
Unmodified PVDF resins have a
shrink rate of about 2-3% depending
on part geometry and thickness.
Engineers must take these values
into account when designing molds
for part production.
Recently, innovations in modifying
PVDF resins have produced
products that have reduced shrink
values. By adding a carbon filler to
the PVDF resin, shrink rates similar
to polypropylene or polyethylene are
obtained. Thus, PVDF can be substituted
into those molds with minimal
process adjustments. Additionally,
glass-reinforced PVDF resins
(Figure 9) strengthen PVDF to yield
a flexural modulus (ASTM D790)
over 1 million psi, similar to that of
PEEK (polyether ether ketone) for a
fraction of the cost. This glass-reinforced
PVDF resin has a very low
shrink rate of less than 1%.
Stock shapes. Rods and sheets
are produced with PVDF resins for
making stock shapes (Figure 10).
These components can be utilized
by component fabricators to create
specialized parts. Rods and
sheets can be cut, formed and machined
into components that have
tight tolerances. Additionally, stock
shapes make PVDF components
available to original equipment
manufacturers (OEMs) that need
the material properties of PVDF
without having to invest in injection
molding equipment.
PVDF sheets are commonly used
in the tank industry. Tanks can be
fabricated using a variety of techniques
from solid PVDF, to linings
on metal or fiberglass-reinforced
tanks. Facilities that have corroding
or rusting metal tanks may find
PVDF sheet linings a viable solution
to retrofit in the existing structure. n
Edited by Gerald Ondrey
TABLE 1. DEFLECTION TEMPERATURE OF FLUOROPOLYMERS* [3]
Def. temp. at 66 psi,°F
Melt point, °F
620
590
554
518
464
352
250
164
158
220
240
298
118
124
165
170
235
At 264 psi,°F
132
TABLE 2. FLEXURAL PROPERTIES OF
PLASTICS*
Material
PVDF homopolymer 740
ECTFE
PVDF copolymer 2850
ETFE
PVDF copolymer 3120
PVDF copolymer 2800
FEP
PFA
PTFE
PVDF copolymer 2750
PVDF copolymer 2500
PVDF copolymer Ultraflex
*ASTM D790 at 73°F
Authors
Averie Palovcak is an applications
engineer for the Technical
Polymers Division of Arkema Inc.
(900 First Avenue, King of Prussia,
PA 19406; Phone: 610-2057026:
Email:
averie.palovcak@
arkema.com). She graduated with
a B.S. and M.S. in biomedical engineering
from Drexel University.
Jason Pomante is the North
American market manager in the
Technical Polymers Division
of
Arkema (same address as
above; Email: jason.pomante@
arkema.com), and has worked
for Arkema for over 15 years. He
graduated from Lafayette College
in 2002 with a B.S.Ch.E.,
and holds an M.B.A. from Saint
Joseph's University in 2010.
References
1. Ebnesajjad, Sina, " Applied Plastics Engineering Handbook, "
, Chapter 4, Introduction to Fluoropolymers, pp.
49-60.
www.fluoroconsultants.com/sitebuildercontent/sitebuilderfiles/introductiontofluoropolymers.pdf.
2.
Sherman, L. M., " Glass Reinforcement Opens New Doors
for PVDF Fluoropolymers, " Plastics Technology. August
26, 2016, www.ptonline.com/articles/glass-reinforcement-opens-
new-doors-for-pvdf-fluoropolymer.
3. Hanselka, R., Williams, R., Bukay, M., Materials of
Construction for Water Systems Part 1: Physical and
Chemical Properties of Plastics,. Ultrapure Water, July
August 1987, pp. 46-50.
4.
www.agcce.com/brochurespdfs/technical/pe-guideenglish.pdf.
5.
Dennis, G., Advanced Industry Applications for PVDF
Based Resins, The IAPD Magazine, April/May 2002,
pp. 29-31.
6. Gruen, H., Burkhart, M., O'Brien, G. Steam Sterilization
of PVDF Piping Systems in PW and WFI for the Pharmaceutical
and Biotechnology Applications, Ultrapure
Water, October 2001.
7. Barbone, R., Morris, S., Seiler, D., Pipe Testing Methods
Put to the Test, Plumbing Systems & Design, September/October
2005.
8. Underwriters Laboratories, " Report on Molded Plastic
Under the
Classification Program, "
12CA32465, August 7, 2012.
FIGURE 9. Glass-reinforced PVDF resin can be
used for bolts
FIGURE 10. PVDF rods can be machined into specialized
components
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
AUGUST 2018
9. Lyndell, C., " Koch Recalls Beef Contaminated with Plastic,.
Food Engineering, April 13, 2018, www.foodengineeringmag.com/articles/97473-koch-recalls-beefcontaminated-with-
plastic.
49
Project Number
Flex modulus, psi
300,000
240,000
170,000
170,000
110,000
100,000
85,000
85,000
72,000
60,000
35,000
10,000

http://www.fluoroconsultants.com/sitebuildercon http://www.ptonline.com/articles/glass-reinforce http://www.agcce.com/brochurespdfs/technical/pe-guide http://www.fooden http://www.gineeringmag.com/articles/97473-koch-recalls-beef http://WWW.CHEMENGONLINE.COM

Chemical Engineering August 2018

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