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Describe the methods of classifying polymeric materials

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Homework Statement



Can anyone advise if this is a satisfactory answer. Ive had a run over it and it does seem rather bulky for the given question.

The Attempt at a Solution



Commercial and marketing:

Polymers can be classified in a variety of different ways. The commercial market are enticed by the use of polymers because of the general affordability of the raw material, the ease of mass market manufacture such as tooth brushes, toothpaste tubes, ear bud sticks etc. The polymers produced are commonly for ‘one-use’ applications, this leads to a continuous stream of revenue for the manufacturer.

Industrial design and application:

Another method of classification is for the industrial design and application market. Once the raw materials for thermoplastic or thermoset plastics have been heated designers can use injection mounding techniques to create shapes that would be difficult to obtain by ordinary secondary finishing techniques.

Physical form of component:

Polymeric materials can be defined In terms of physical form into the below six groups.

Plastics

Thermosetting plastics – Once initially heated the thermosetting plastic shares thermoplastic properties, however, once the plastic has solidified and cooled sufficiently it becomes resistant to heat. Once a sufficient amount of heat has been applied to the resultant product it will thermally decompose.

Thermoplastics – Once a thermoplastic has cooled it can be re-heated to the glass transition temperature , after reaching this point the material will soften and become malleable ready for repurposing (reuse).

Rubbers

Rubber can be defined as natural rubber (NR) or synthetic rubber (SBR) or (CR). Rubber are most commonly used in the ‘cured’ or ‘vulcanised’ form. This is where the rubber molecules have formed chemical cross links to other rubber molecules. The resultant being a three dimensional open molecular network.

Textile Fibres

Natural fibres – Most commonly used in fabrics, ropes and twines.

Synthetic fibres - Thermoplastic in origin. These spun and weaved into threads.



Adhesives + Coatings

Either natural or man-made. Adhesives and coatings can come from any of the previously mentioned ‘types’. The materials can be a designed combination of all different polymeric materials. Such as PF, epoxy resin, NR and combinations of the same.

Composite Materials

Composites are designed combinations of polymeric materials and other constituents such as glass fibre. These provide different properties that can be applied to various different situations.

Material Structure:

Amorphous Thermoplastics

These have branched polymer molecules that do not crystallise into a solid configuration. Thus, having no crystalline melting point . However, they have various ‘softening’ points, including

Low-Crystallinity Thermoplastics

Mostly consisting of PVC polymers. Fitting between the amorphous and crystalline thermoplastics. They also have the softening points of However, they also have a melting transition at .

Crystalline Thermoplastics

Whilst in the crystalline state, the polymer chains have a higher visco-elastic mannerism. Textile fibres would be included in this Crystalline Thermoplastics section.

Thermosetting polymers

The tri-dimensional molecules produced during the forming and curing prohibit crystallisation. Such materials do not poses a melting point . or a softening point thus are normally brittle.

Rubbery Materials.

Firstly being amorphous thermoplastics, they transition to rubbery materials once vulcanised/cured this giving the polymer the very flexible, open and interconnected network of molecules. Thus the material assumes it’s rubbery properties.
 

Answers and Replies

  • #2
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rather bulky for the given question.
It's a "rather bulky bulky" material properties area, and growing bulkier by the day/minute/hour (rapidly). Compare the variety of today to that of a century ago, and how many orders of magnitude are we discussing?
 

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