Polymer engineering
Polymer engineering is generally an engineering field that designs, analyses, and modifies polymer materials. Polymer engineering covers aspects of the petrochemical industry, polymerization, structure and characterization of polymers, properties of polymers, compounding and processing of polymers and description of major polymers, structure property relations and applications.
History
The word “polymer” was introduced by the Swedish chemist J. J. Berzelius. He considered, for example, benzene (C6H6) to be a polymer of ethyne (C2H2). Later, this definition underwent a subtle modification.[1]
The history of human use of polymers has been long since the mid-19th century, when it entered the chemical modification of natural polymers. In 1839, Charles Goodyear found a critical advance in the research of rubber vulcanization, which has turned natural rubber into a practical engineering material.[2] In 1870, J. W. Hyatt uses camphor to plasticize nitrocellulose to make nitrocellulose plastics industrial. 1907 L. Baekeland reported the synthesis of the first thermosetting phenolic resin, which was industrialized in the 1920s, the first synthetic plastic product.[3] In 1920, H. Standinger proposed that polymers are long-chain molecules that are connected by structural units through common covalent bonds.[4] This conclusion laid the foundation for the establishment of modern polymer science. Subsequently, Carothers divided the synthetic polymers into two broad categories, namely a polycondensate obtained by a polycondensation reaction and an addition polymer obtained by a polyaddition reaction. In the 1950s, K. Ziegler and G. Natta discovered a coordination polymerization catalyst and pioneered the era of synthesis of stereoregular polymers. In the decades after the establishment of the concept of macromolecules, the synthesis of high polymers has achieved rapid development, and many important polymers have been industrialized one after another.
Classification
The basic division of polymers into
Thermoplastics
Elastomers
An
Thermosets
A thermosetting resin is used as a main component, and a plastic which forms a product is formed by a cross-linking curing process in combination with various necessary additives. It is liquid in the early stage of the manufacturing or molding process, and it is insoluble and infusible after curing, and it cannot be melted or softened again. Common thermosetting plastics are phenolic plastics, epoxy plastics, aminoplasts, unsaturated polyesters, alkyd plastics, and the like. Thermoset plastics and thermoplastics together constitute the two major components of synthetic plastics. Thermosetting plastics are divided into two types: formaldehyde cross-linking type and other cross-linking type.
Thermosets includes
Materials
Plastic
Fiber
Fiber refers to a continuous or discontinuous filament of one substance. Animals and plant fibers play an important role in maintaining tissue. Fibers are widely used and can be woven into good threads, thread ends and hemp ropes. They can also be woven into fibrous layers when making paper or feel. They are also commonly used to make other materials together with other materials to form composites. Therefore, whether it is natural or synthetic fiber filamentous material. In modern life, the application of fiber is ubiquitous, and there are many high-tech products.[8]
Rubber
Applications
Polyethylene
Commonly used polyethylenes can be classified into low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE). Among them, HDPE has better thermal, electrical and mechanical properties, while LDPE and LLDPE have better flexibility, impact properties and film forming properties. LDPE and LLDPE are mainly used for plastic bags, plastic wraps, bottles, pipes and containers; HDPE is widely used in various fields such as film, pipelines and daily necessities because its resistance to many different solvents.[9]
Polypropylene
Polypropylene is widely used in various applications due to its good chemical resistance and weldability. It has lowest density among commodity plastics. It is commonly used in packaging applications, consumer goods, automatic applications and medical applications. Polypropylene sheets are widely used in industrial sector to produce acid and chemical tanks, sheets, pipes, Returnable Transport Packaging (RTP), etc. because of its properties like high tensile strength, resistance to high temperatures and corrosion resistance.[10]
Composites
Biomedical applications
Membrane technologies
Related Major
- Petroleum / Chemical / Mineral / Geology
- Raw materials and processing
- New energy
- Automobiles and spare parts
- Other industries
- Electronic Technology / Semiconductor / Integrated Circuit
- Machinery / Equipment / Heavy Industry
- Medical equipment / instruments
See also
- Plastics engineering
- Polymer science
- Polymers
- Medical grade silicone
- Category:Polymer scientists and engineers
References
- ISSN 0021-9584.
- OCLC 1075130719.
- PMID 16504284.
- ISBN 9780387738604
- ^ "Thermoplastics :: PlasticsEurope". www.plasticseurope.org. Retrieved 2019-01-25.
- OCLC 1040036368.
- ISBN 9780203428504.
- S2CID 4392276.
- S2CID 4392276.
- ^ "Polypropylene (PP) Plastic: Types, Properties, Uses & Structure Info". omnexus.specialchem.com. Retrieved 2019-03-17.
- ^ "Polymer Technologies Receives 2012 Boeing Award".
- OCLC 1011405606.
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Bibliography
- Lewis, Peter Rhys, and Gagg, C, Forensic Polymer Engineering: Why polymer products fail in service, Woodhead/CRC Press (2010).