Glossary of Terms :: TBL Performance Plastics

Glossary

Acrylonitrile-Butadiene-Styrene (ABS): A rigid thermoplastic polymer common in piping applications. It is the counterpart to off-white PVC pipe; ABS pipes are black. ABS is very durable but breaks down when exposed to acetone.

Aseptic processing: is the process by which a sterile product such as food or pharmaceutical is packaged in a sterile container in a way that maintains sterility.

Abrasion Resistance: The ability a material has to withstand rubbing and scraping. Polyurethane (TPU) Tubing has a high level of abrasion resistance.

Annealing: process of heating of a material, below the melting point, to reconfigure molecules, re-setting the material’s “memory” or creating new bulk or interfacial crystal lattices.

ASTM: American Society of Testing Materials is a globally recognized creator of standards for a wide range of material testing methods.

Bend Radius: The minimum radius of a half circle about which a tube can be bent before it kinks. In general, a smaller bend radius corresponds to a more flexible tube.

Bloom: The residue that in time comes out of plastics that contain plasticizers, stabilizers or lubricants such as Vinyl (PVC). Sometimes called a “haze.”

Butt Weld: A joint in a plastic tube or tether that is created by melting two ends and then joining them together, end-to-end. The result is a bond as strong as the original material.

CCAI: Chemical Coater’s Association International

Coefficient of Thermal Expansion: the unit change in length or volume resulting from a unit change in temperature>

Co-extrusion: a process of extruding two materials simultaneously through the same die.

Coiled Hose: a type of tubing that has reinforcement like a coiled metal thread or similar.

Compressive Strain: The resulting deformation of compressive stress acting on a material

Compressive Stress: Stress that acts to shorten an object

Creep: measured at constant stress and temperature, creep is a measure of deformation over time. Creep always increases with temperature.

DEHP: Bis (2-ethylhexyl) phthalate, commonly abbreviated DEHP, is classified as a phthalate. It is a commonly used as a plasticizer for polymers such as PVC, but has been banned in some places such as the European Union due to health concerns. The ban is known as REACH. TBL offers Vinyl Tubing with No DEHP or Phthalates.

Dielectric Strength: The minimum voltage required to produce current through a material. A higher dielectric strength indicates a better insulator

DOP: dioctyl phthalate, see “DEHP”

Ductility: a measure of the deformation of a material under tensile (pulling) stress

Durometer: a measure of the hardness of a material. The three main scales for measuring hardness are, Shore A, Shore D and Rockwell

Elasticity: a measure of the tendency of a material to return to its original shape after being bent or stretched

Elongation: See “Tensile Elongation”

Extender: A material added to a polymer base that is designed to replace a portion of the polymer compound. Also known as “filler.” TBL does not use extenders.

Extrusion: The process of drawing out melted plastic in to useful shapes such as tubing.

Flame Rating (UL 94): UL flame ratings group materials based on their flammability. UL 94 flame ratings cover both horizontal and vertical testing. Click here to read more.

Flexural Modulus: The ratio of stress to strain that occurs while a stress is acting to bend an object. Materials with lower flexural moduli tend to be more flexible.

Flexural Strength: The ability of a material to resist deformation under a load.

FEP: or fluorinated ethylene propylene an alternative to Teflon® tubing. (Teflon® is a registered trademark of DuPont.) FEP tubing is known for chemical resistance and ability to withstand a large range of temperatures.

Gamma Stable: The ability to resist a change in physical properties under gamma irradiation. Typically gamma irradiation is used in the plastics industry to sterilize tubing or process components in an aseptic container. Commonly acceptable doses range between 25 kGy and 55 kGy

Heat Deflection Temperature: a test in which a horizontal bar of a polymer is heated uniformly in a closed chamber while a load of 66psi or 264psi is placed at the center of the bar. The HDT is the temperature where a deflection of 0.25mm is reached at the center. The HDT is an indicator of how much mass an object must be constructed of to maintain desired structural integrity. Also, it provides a measure of rigidity of a material under a load at a certain temperature.

HDPE: high density polyethylene

Hook’s Law: Discovered by Robert Hook, this law states that for small deformations of an object, the size of the deformation is directly proportional to the force applied to the object (e.g. if the force is doubled then the size of the deformation is doubled) within an initial region. The deformation force can include stretching, compression, squeezing, bending, or pulling. After the directly proportional region Hook’s law does not apply. It is interesting to note that within the linear region the object will theoretically return to it’s original shape following the removal of the deforming force.

Hose: Tubing constituted by two or more distinguishable materials.

ILDA: Independent Laboratory Distributors Association www.ilda.org

Inner-braid: A woven textile that is inside a composite or co-extruded tube providing reinforcement.

Kynar®: A trade mark of Arkema Chemical Corp. Kynar® tubing is an economic alternative to PTFE tubing.

LDPE: Low Density Polyethylene

Limiting Oxygen Index: a minimum oxygen requirement to facilitate the combustion of a material.

LLDPE: Linear Low Density Polyethylene. More durable than LDPE

Memory: The tendency a particular plastic has to go back to its original shape after being stretched or bent.

Modulus of Elasticity: The ratio of stress to strain that occurs when a stress is applied to a material. While a stress is acting on a material a material, initially the relationship between the applied force (stress) and the disturbance (strain) is linear (it is directly proportional), but after the material is strained to a certain point, the relationship is no longer linear (this phenomenon is known as Hooke’s Law) .

Normal Stress: A stress acting perpendicular to a surface including compression and tension (pulling)

Nylon: There are five main types of nylon, including: 6/6, 6, 6/12, 11 and 12. Nylon is valued for its strength and low cost. It is very abrasion resistant when used as braiding.

Peristaltic Pump: Sometimes referred to as a hose pump. Fluid is moved through tubing by rollers that compress the tube, in a rotary housing. A primary advantage of this type of pump is that it has very low sheer characteristics and the tube can be easily sterilized. These types of pumps are used extensively in the pharmaceutical industry for metering and medical applications for biological fluids. TBL features a range of Peristaltic-Pump Tubing.

Permeability: a measure of the ability of a material to pass pressurized liquid or gas through its walls.

Phthalate: A common substance added to some plastics (usually PVC) to increase flexibility. It doesn’t bond with the plastic so over time it may be released into the environment. There are studies linking phthalates to a variety of ailments, particularly in children. Although, most tubing materials are phthalate-free by nature, some types of tubing are ridden with phthalates, such as flexible PVC. Early in 2011, TBL was among the first few companies to commercialize a phthalate-free PVC tubing product.

Plasticizer: A chemical added to a plastic to improve flexibility and lower glass transition temperature. For example, a plasticizer is added to PVC to change it from rigid to flexible.

Polycarbonate: A high impact thermoplastic resin used in making “bulletproof glass” and microwave cookware.

Polyester: A large classification of resins that are used for making textile fibers. Not a tubing compound.

Polyethylene: Polyethylene is an economical plastic that, when extruded in to tubing, is useful in a multitude of applications, such as laboratory applications, potable water, chemical process, and even some bio-pharmaceutical applications. TBL manufactures LDPE and LLDPE tubing, but LLDPE is commonly prefered over LDPE for tubing for several reasons. Learn more about the differences between LDPE and LLDPE tubing.

Polymer: The generic word used to describe many plastics. Specifically, a polymer can be natural or synthetic. The compounds are formed from many low molecular weight monomers that are combined into long molecular chains.

Polypropylene (PP): a tough, light weight commodity thermoplastic known for its low price and chemical resistance.

Polytetrafluroethylene (PTFE): A highly chemically resistant plastic, also known for having the lowest coefficient of friction of almost all known polymers. PTFE tube is ideal for a broad range of uses from bio-pharm to high purity industrial chemical applications. It is commonly referred to as Teflon®, which is a registered trademark of DuPont Chemical.

Polyurethane: A thermoplastic noted for its high resistance to abrasion while being highly flexible and kink resistant. Available in both an ether and ester base. The ester-based PUR is less desirable due to how it degrades in moisture. The ether-based polymer is much more durable.

Polyvinyl Chloride (PVC): PVC is a tasteless and odorless polymer that will not degrade in many organic solvents. When a plasticizer is added, the PVC becomes flexible with good abrasion resistance.

Recovery: the degree to which a plastic returns to its original shape after a load is removed.

Resin: the “raw” form of plastic, commonly supplied in pellet form

Retracted Length: the length of a coil at rest

Rockwell Hardness: a durometer measuring scale developed by the Rockwell Corporation. Rockwell hardness is measured by testing the resistance of a material to being punctured.

RoHS: the Restriction of Hazardous Substances commonly used in Electrical and Electronic Equipment. Learn more about country specific guidelines on RoHS.

Shear: stress acting parallel to a surface

Shore Hardness: A measure of hardness (Shore A and Shore D) developed by the Shore Instrument Company

Silicone: A flexible thermoset plastic with high thermal stability, water resistance, flexibility and low toxicity that is commonly used in medical and peristaltic pump applications. Most silicone tubing fits within the categories platinum-cured silicone and peroxide-cured silicone. TBL offers each type of material in braid-reinforced or non-reinforced.

SME: Society of Manufacturing Engineers

Stress Relaxation: a measurable decrease in stress exerted by a material over time at a constant temperature.

Sterilization: any process that eliminates or kills all forms of microbial life, including transmissible agents (such as fungi, bacteria, viruses, spore forms, etc.) present on a surface, contained in a fluid, in medication, or in a compound such as biological culture media. Sterilization can be achieved by applying combinations of heat, chemicals, irradiation, high pressure, and filtration.

Strain (in materials engineering): The change in a material as a result of an applied stress

Stress (in materials engineering): A force applied to a material.

Specific Gravity (SG): the ratio of the weights of two particular samples of equal volume. In many cases, the standard is water (the specific gravity of water is 1 at 4⁰C and 1 atm.)

Tensile Modulus: The ratio of stress to strain that occurs when a material is being pulled. Materials with a lower tensile modulus tend to elongate more with a lower applied force.

Tensile Strain: The resulting deformation of a material due to tensile stress

Tensile Stress: The application of a pulling force to an object, measured in force per unit area

Teflon®: A brand name of PTFE, registered by the DuPont Chemical Company. Teflon® is highly chemical and temperature resistant.

Thermal Conductivity: A constant that indicates the measure of heat energy that will travel from one surface to another through a substance. Thermal conductivities are tabulated in literature for many liquids, solids and gasses. It has units of Watts/(Meter*K).

Thermoplastic: a plastic that can be melted and re set when cooled. Thermosets can not be melted and reformed as they burn before the melting temperature.

Thermoplastic Elastomer (TPE): a thermoplastic that has characteristics similar to rubber. Unlike rubber, they can be repeatedly reshaped like a thermoplastic.

Tensile Elongation: The percentage increase in length of a material that occurs before the material breaks under tensile stress.

Tensile Strength: a measure of the ability a tube has to sustain tension (pulling).

Tensile Strength at Break (Ultimate Tensile Strength): The force per unit area (psi or MPa) required to break a material by applying a pulling force. It is a considerable factor in calculating burst pressure. Read more about ultimate tensile strength.

Total Organic Carbon (TOC): a measure of bound carbon within an organic compound such as a plastic

Tolerance ( In Engineering): the permissible limit of variation in units of measure

TPE: see “thermoplastic elastomer”

TPV: Thermoplastic Vulcanite

Thermoset: A polymer that can not be melted and reformed (commonly due to crosslinking or additives). Thermosets can burn at lower temperatures than they melt.

UL 94 Flame Rating: See “Flame Rating”

Vicat Softening Point:

Viscosity: The resistance of a material to flow. Fluids that are highly viscous do not flow well. Water has a relatively low viscosity compared to a material such as toothpaste.

Vulcanization: a chemical crosslinking reaction in plastic that occurs when exposed to sulfur, making soft plastic harder. A thermoplastic that is vulcanized turns in to a thermoset.

Working Length: the length of a coil when it is stretched to its maximum length

Working Pressure: At a given temperature, working pressure is the maximum pressure at which tubing can be expected to perform without sacrificing performance.
Young’s Modulus: See “Modulus of Elasticity”