In
materials science
Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries.
The intellectual origins of materials sci ...
, a polymer blend, or polymer mixture, is a member of a class of materials analogous to metal
alloy
An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
s, in which at least two
polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...
s are blended together to create a new material with different physical properties.
History
During the 1940s, '50s and '60s, the commercial development of new monomers for production of new polymers seemed endless. In this period, it was discovered that the development of the new techniques for the modification of the already existing polymers, would be economically viable.
The first technique of modification developed was the polymerization, in other words, the joint polymerization of more than one kind of polymer.
A new polymers modification process, based on a simple mechanical mixture of two polymers first appeared when
Thomas Hancock created a mixture of natural rubber with
gutta-percha
Gutta-percha is a tree of the genus ''Palaquium'' in the family Sapotaceae, which is primarily used to create a high-quality latex of the same name. The material is rigid, naturally biologically Chemically inert, inert, resilient, electrically n ...
. This process generated a new polymer class called "polymer blends."
Basic concepts
Polymer blends can be broadly divided into three categories:
* immiscible polymer blends (heterogeneous polymer blends): This is by far the most populous group. If the blend is made of two polymers, two
glass transition temperature
The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rub ...
s will be observed.
* compatible polymer blends: Immiscible polymer blends that exhibit macroscopically uniform physical properties. The macroscopically uniform properties are usually caused by sufficiently strong interactions between the component polymers.
*
miscible polymer blends (homogeneous polymer blends): Polymer blend that is a single-phase structure. In this case, one glass transition temperature will be observed.
The use of the term polymer alloy for a polymer blend is discouraged, as the former term includes multiphase copolymers but excludes incompatible polymer blends.
Examples of miscible polymer blends:
*
homopolymer–homopolymer:
**
polyphenylene oxide (PPO) –
polystyrene
Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It i ...
(PS):
noryl developed by
General Electric
General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston.
Over the year ...
Plastics in 1966 (now owned by
SABIC). The miscibility of the two polymers in noryl is caused by the presence of an aromatic ring in the
repeat units of both chains.
**
polyethylene terephthalate
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in synthetic fibre, fibres for clothing, packaging, conta ...
(PET) –
polybutylene terephthalate (PBT)
**
poly(methyl methacrylate)
Poly(methyl methacrylate) (PMMA) is a synthetic polymer derived from methyl methacrylate. It is a transparent thermoplastic, used as an engineering plastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and bran ...
(PMMA) –
polyvinylidene fluoride (PVDF)
* homopolymer–
copolymer:
**
polypropylene
Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer Propene, propylene.
Polypropylene belongs to the group of polyolefin ...
(PP) –
EPDM
EPDM rubber (ethylene propylene diene monomer rubber) is a type of synthetic rubber that is used in many applications.
EPDM is an M-Class rubber under ASTM standard D-1418; the ''M'' class comprises elastomers with a saturated and unsaturated co ...
**
polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate ester, carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, toughness, tough materials, and some grades are optically transp ...
(PC) –
acrylonitrile butadiene styrene (ABS): Bayblend, Pulse, Anjablend A''
Polymer blends can be used as
thermoplastic elastomers.
See also
*
Flory–Huggins solution theory
*
Emulsion dispersion
References
External links
* Miscible polymer blends: http://pslc.ws/macrog/blend.htm
* Immiscible polymer blends: http://pslc.ws/macrog/iblend.htm
Polymers
{{polymer-stub