Thermoplastic Materials

THERMOPLASTIC MATERIALS

A THERMOPLASTIC IS A TYPE OF PLASTIC MADE UP OF POLYMER RESINS THAT BECOMES SOFT AS THE MATERIAL IS HEATED AND HARD AS IT IS COOLED. THESE MATERIALS DO NOT SHOW ANY CHEMICAL PROPERTY CHANGES WHEN HEATED OR COOLED MULTIPLE TIMES, MAKING THEM MORE SUITABLE FOR RECYCLING.

Thermoplastic materials can be homogenous and heterogeneous in their makeup. Unique properties can be achieved by blending thermoplastics, co-extruding, or including special property-enhancing additives.

Thermoplastics can be manufactured and fabricated using several standard methods. Most thermoplastic sheet and film is produced using an extrusion process. Cast methods can also produce some sheet materials. Nearly any sheet thermoplastic material can be formed by using thermoforming, vacuum forming, or cold forming methods. Thermoplastics with or without reinforcement can also be injection molded into complicated shapes with features not achievable through standard machining.

Thermoplastic materials are suitable for numerous applications – aerospace, defense, medical, satellite communications, food service, and electronics being just a few industries that utilize thermoplastics. Although thermoplastics are often processed similarly, performance characteristics, workability, and cost can vary greatly.

AMORPHOUS VS. SEMI-CRYSTALLINE

Thermoplastics can be broken into two groups by composition: Amorphous and Semi-Crystalline thermoplastics.

While the molecules in semi-crystalline polymers are clustered and structured in a region, the molecules in amorphous polymers are randomly arranged.

AMORPHOUS:

Easy to thermoform
Typically translucent
Softens over a range of temperatures
Bonds well using adhesives
Good for structural applications
Poor fatigue resistance
Not ideal for wear applications
Subject to cracking from stress

SEMI-CRYSTALLINE:

Challenging to thermoform
Typically opaque
Sharp melting point
Difficult to bond
Good for structural applications
Good fatigue resistance
Good for wear & bearing applications
Good resistance to cracking from stress

AMORPHOUS THERMOPLASTICS:

Amorphous thermoplastics are more conducive to thermoforming. They soften over a range of temperatures and have better bonding ability when combined with adhesives.

Amorphous plastics often have better dimensional stability and impact resistance than semi-crystalline thermoplastics of a similar grade. However, stress makes amorphous plastics more prone to fatigue and cracking.

SEMI-CRYSTALLINE THERMOPLASTICS:

Semi-Crystalline thermoplastics are excellent for wear and structural applications.

Compared to amorphous thermoplastics, these semi-crystallines tend to have better chemical resistance, electrical properties, and a lower coefficient of friction. However, semi-crystalline plastics are challenging to thermoform, difficult to bond, have a sharp melting point, and have lesser impact strength.

PLASTIC FAMILIES:

Thermoplastics can be further categorized into families by temperature rating.

Each family comprises amorphous and semi-crystalline plastics with distinct advantages and disadvantages, depending on what is trying to be achieved.,

COMMODITY THERMOPLASTICS:

AT THE BOTTOM OF THE PYRAMID, COST-EFFECTIVE COMMODITY PLASTICS SUCH AS PP, PE, PVC, PS, AND PET POLYMERS ARE FOUND IN SEMI-CRYSTALLINE AND AMORPHOUS FORMS.

These plastics don’t require highly-engineered properties and are produced at larger volumes to support many everyday applications.

Although the operating temperature of these materials is lower and they are generally weaker than higher-performing plastics, they can offer good chemical resistance and machinability (although there is variability between commodity plastics). Commodity thermoplastics are by far the most common plastic and are widely used worldwide.

APPLICATIONS:

Textiles
Automotive
Toys
Containers
Electronics
Construction
Housewares

Commodity Thermoplastics
Description	Test Method	Units	pp	PETG	HDPE	ABS
Specific Gravity	ASTM D792	—	0.905	1.27	0.95	1.04
Water Absorption	ASTM D570	%	<0.01	0.2	<0.01	1
Hardness, Rockwell	ASTM D785	—	92	115	69	105
Tensile Strength	ASTM D638	psi	4800	7700	4800	6000
Elongation at Break	ASTM D638	%	12	18	900	150
Flexural Modulus	ASTM D790	ksi	180	310	200	340
Flexural Yield Strength	ASTM D790	psi	7000	11200	—	10000
Compressive Modulus	ASTM D695	ksi	—	320	—	—
Impact Strength	ASTM D256	ft-Ib/in	1.9	1.7	3	2.5
Dielectric Constant	ASTM D150	—	2.25	2.6	2.3	2.7
Dielectric Strength	ASTM D149	kV/m	660	410	900	500
Dissipation Factor	D150	—	0.001	0.005	0.0002	0.01
Coefficient of Thermal Expansior	D696	x10^-5in./in/F*	6.2	3.8	6	5
Heat Deflection Temp	D648	F	210	163	170	198
Glass Transition Temp	D3418	F	327	180	260	221
Max Operating Temp	—	F	180	150	180	176
Thermal Conductivity	AST F433	BTU-in/hr-ft^2-F	0.8	2	2.92	1.73

Other Commodity Thermoplastic Materials include
	PolyPro FR®	Formex®
	Vivak®

Contact Us Today to learn more about commodity thermoplastic materials from The Gund Company or request a quote for your application!

ENGINEERING THERMOPLASTICS

ALTHOUGH THEY SHARE MANY SIMILARITIES WITH COMMODITY THERMOPLASTICS, ENGINEERING THERMOPLASTICS ARE DESIGNED FOR ENVIRONMENTS THAT REQUIRE HIGHER STRENGTH, TEMPERATURE RESISTANCE, AND DURABILITY, AMONG OTHERS.

Common engineering plastics include polycarbonate, nylon (PA), acetal (POM), and UHMW-PE.

Variation in characteristics between these materials does exist, but in general, they are all used in environments unsuitable for commodity thermoplastics. Engineering thermoplastics are generally more expensive than commodity thermoplastics, but both are relatively inexpensive.

APPLICATIONS:

Bearings, Springs, Valves
Automotive
Medical/Healthcare
Textiles
Electronics
Cookware

Engineered Thermoplastic
Description	Test Method	Units	pC	Nylon	Acetal	UHMW
Specific Gravity	ASTM D792	—	1.2	1.15	1.41	0.93
Water Absorption	ASTM D570	%	0.15	0.3	0.2	<.01
Hardness, Rockwell	ASTM D785	—	118	115	120	66
Tensile Strength	ASTM D638	psi	9000	11500	9500	3100
Elongation at Break	ASTM D638	%	110	50	30	30
Flexural Modulus	ASTM D790	ksi	345	450	400	125
Flexural Yield Strength	ASTM D790	psi	13500	15000	12000	—
Compressive Modulus	ASTM D695	ksi	345	420	400	—
Impact Strength	ASTM D256	ft-Ib/in	18	0.6	1	N/A
Dielectric Constant	ASTM D150	—	2.96	3.6	3.8	2.3
Dielectric Strength	ASTM D149	kV/m	380	15.7	420	900
Dissipation Factor	D150	—	0.0009	0.02	0.005	0.00002
Coefficient of Thermal Expansior	D696	x10^-5in./in/F*	0.375	5.5	5.4	11
Heat Deflection Temp	D648	F	280	200	220	95
Glass Transition Temp	D3418	F	310	500	335	280
Max Operating Temp	—	F	300	210	180	180
Thermal Conductivity	AST F433	BTU-in/hr-ft^2-F	1.35	1.7	1.6	2.92

Other Engineered Thermoplastic Materials include
	Zytel®	Lexan®
	Valox®	Mylar®
	Statex®	Delrin®

To learn more about engineering thermoplastic materials from The Gund Company or to request a quote for your application, Contact Us Today.

HIGH PERFORMANCE AND IMIDIZED

HIGH-PERFORMANCE PLASTICS AND IMIDIZED PLASTICS MAY BE NECESSARY FOR MORE DEMANDING OR SPECIALIZED APPLICATIONS.

High-performance plastics such as PEEK, PTFE, and PSS can withstand very high temperatures and offer excellent chemical resistance.

Imidized plastics are often suited more for aerospace applications but can also be used for thermal insulators, high-performance bearings, and electrical connectors in extreme environments. Imidized plastics such as polyamide-imide (PAI), polybenzimidazole (PBI), and polyimide (PI) feature the highest temperature resistance and load-bearing capabilities, among other properties.

APPLICATIONS:

Aerospace
Insulation
Wear Components
Electronics
Food Service
Medical

			Imidized Plastics			High Performance Plastics
Description	Test Method	Units	PI	PAI	PBI	PEEK	PTFE	Ultem
Specific Gravity	ASTM D792	—	1.43	1.41	1.3	1.31	2.16	1.28
Water Absorption	ASTM D570	%	0.24	0.4	0.4	0.1	<0.01	0.25
Hardness, Rockwell	ASTM D785	—	50	80	125	103	50	112
Tensile Strength	ASTM D638	psi	12500	18000	20000	16000	3900	16500
Elongation at Break	ASTM D638	%	7.5	10	3	20	300	80
Flexural Modulus	ASTM D790	ksi	450	600	950	600	72	500
Flexural Yield Strength	ASTM D790	psi	16000	24000	32000	25000	N/A	20000
Compressive Modulus	ASTM D695	ksi	350	700	900	500	3.5	480
Impact Strength	ASTM D256	ft-Ib/in	3.76	2	0.5	1	3.5	0.5
Dielectric Constant	ASTM D150	—	3.55	4.2	3.2	3.3	2.1	3.15
Dielectric Strength	ASTM D149	kV/m	559	580	550	480	285	830
Dissipation Factor	D150	—	—	0.026	0.003	0.003	<0.0002	0.0013
Coefficient of Thermal Expansior	D696	x10^-5in./in/F*	3	1.7	0.13	2.6	7.5	3.1
Heat Deflection Temp	D648	F	—	532	800	320	132	392
Glass Transition Temp	D3418	F	754	527	750	644	635	419
Max Operating Temp	—	F	466	500	700	480	500	340
Thermal Conductivity	AST F433	BTU-in/hr-ft^2-F	—	3.7	2.8	1.75	1.7	0.9

Other Materials include
	Torlon®	Udel®
	Teflon®	Kynar®
	Vespel®	Radel®
	PEEK®	Rulon®

Contact Us Today to learn more about high-performance or imidized thermoplastic materials from The Gund Company, or to request a quote for your application!