What is dimensional stability of plastic?
Dimensional stability refers to the ability of polymers to maintain their size, even under varying environmental conditions. As a result, a dimensionally stable plastic shows low water absorption with low thermal expansion.
Is PVC dimensionally stable?
PVC foam-Mica composites were characterized for their dimensional stability, and structural, thermal, and mechanical properties. Experimental results showed that the dimensional stability increased by 44% and heat resistance of the samples improved as the amount of mica increased in the composites.
Is nylon dimensionally stable?
Nylon 4/6 absorbs more water than nylon; however, its dimensional stability is similar to nylon 6/6 due to its high crystallinity. Nylon 4/6, with its unusually high crystallinity, maintains a higher level of performance at elevated temperatures. The HDT for reinforced nylon 4/6 is 545°C.
Does POM absorb water?
Physical and Mechanical Properties POM is not hygroscopic and water absorption is very low, dimensional stability is good with changes in humidity. POM has a relatively high density of 1.41 and POM parts are heavier than equivalent parts in other plastics.
What is good dimensional stability?
Metals with good dimensional stability are tough and rigid with minimal response to wear and tear over prolonged periods of use. This is characterized by maintenance of its original pleating and shape, with minimal shrinkage or plasticity.
Is acrylic dimensionally stable?
Dimensional stability of acrylic The dimensions of acrylic does not change significantly over time, hence many measuring instruments is manufactured in acrylic. If acrylic is fixed in a steel frame, there is a high probability that the acrylic will crack if the temperature changes.
Is HDPE dimensionally stable?
Although high density polyethylene (HDPE) is one of the most widely used industrial polymers, its application compared to its potential has been limited because of its low dimensional stability particularly at high temperature.
Is POM plastic recyclable?
Also known as Polyacetal, polyformaldehyde and Acetal, POM is an engineering thermoplastic used in precision parts. POM applications are 100% recyclable, either as feedstock or mechanically.
Does POM contain formaldehyde?
What is a Polyacetal? Polyacetal, also commonly known as acetal or polyoxymethylene (POM), is a formaldehyde-based, semi-crystalline engineering thermoplastic which contains the functional group of a carbon bonded to two -OR groups. It is 100% recyclable.
What is poor dimensional stability?
What is the Dimensional Stability of Fabrics? The fabric with poor dimensional stability is usually shown as shrinkage, such as shrinkage in sewing, ironing, washing and so on. Among them, the wash shrink is the problem that consumer pays close attention to very much.
Which is an example of a dimensionally stable plastic?
As a result, a dimensionally stable plastic shows low water absorption with low thermal expansion. Examples of dimensionally stable plastics include polymers such as PEEK, PPS, PSU, PPSU, PEI and PET. Moisture absorption (also known as water absorption) is the capacity of a material to absorb moisture from its environment.
How does moisture affect the dimensions of plastic?
The degree of moisture absorption depends on the type of plastic and the ambient conditions such as temperature, humidity and contact time. Not only can dimensions change due to moisture absorption, but also material properties, such as mechanical strength, electrical conductivity and the dielectric loss factor, can be also affected.
Why do plastics have a higher thermal expansion than metals?
Thermal expansion The coefficient of linear thermal expansion specifies the extent of the change in length of a material due to increasing or decreasing temperature. Due to their chemical structure, plastics generally demonstrate a significantly higher coefficient of linear thermal expansion than metals.
How are polyamides different from other engineering plastics?
Polyamides (nylons) generally show higher water absorption than other engineering plastics. This leads to dimensional changes to finished parts, a reduction in strength, and also to changes in electrical insulating characteristics.
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