Sunday 15-09-2019

NIKK Knowledge Base: S

You are currently at the letter S of the Nikk Knowledge base. If you require further information we are pleased to help you - please do not hesitate contacting us.

Sand blasting
Polyolefins like PE and PP could not be glued. But due to surface modification e.g. sand blasting the surface will be chemically modified so that gluing is possible.

Self-supporting
The renovation of statically instable underground pipes is performed by means of statically stable and self-supporting plastic pipes.

Service life
Every polymer has a defined service life depending on temperature, pressure, chemical stress, abrasion and outdoor exposure.

Service life analysis

The service life of a plastic component is influenced by the working conditions like temperature, mechanical and chemical stress. To estimate the service life of a polymer a lot of practical experience is necessary. For the estimation of the remaining service life of a plastic component different methods are available.
NIKK could also measure the remaining service life of plastics.

Shrinkage
Shrinkage or mould shrinkage is the contraction of a moulded part due to cooling down and re-crystallization.

Slide bearing
A slide bearing is a bearing without rolls were e.g. a shaft rotates or moves in a plug socket. Polymers offer good properties for slide bearings.

Slipping
Many materials like metals, glass or wood could slide on polymers very easily because of the low friction coefficient.
Polymers with low friction coefficient are:
- PTFE
- PE-HMW
- PE-UHMW

Solid matter
Solid matter is non-melting additive in polymers to increase the fabrication properties or to modify polymers resulting in special properties.

Sound velocity
The sound velocity cg is defined as the velocity of sound in a matter. The sound velocity of polymers depends on E-Modulus E and density ρ:
Cg=√(E/ρ)

Static and dynamic calculation of polymers
There exist different methods calculating the load and the respond on the load of polymer structures. The properties of polymers differ a lot from that of metals or ceramics. Hence existing different methods calculating static loaded plastic components.
Due to long practical experience of NIKK we could calculate mechanically loaded components like cover plates, carrier, pipe works and tanks. Additionally NIKK has as well the opportunity to support you in the production.

Static load
The static load is a time independent load on a component or construction. A load could occur as a tensile, pressure or shear force.

Stress corrosion
Stress corrosion is well-known for metals, glass and polymers by means. It describes a physical process where the binding energies in-between atoms or molecules are decreased. For the crack growth lower forces are needed.

Styrene
Styrene is chemically speaking phenylethene. At normal atmosphere it is a colourless liquid with a characteristic odour. Styrene is used in a large range of polymers. The most popular is polystyrene. Furthermore it is used in ABS (Acrylnitrile-Butadiene-Styrene), AAA (Acrylonitrile-Styrene) und SAN (Styrene-Acrylnitrile). In reaction resins (thermosets) styrene is used as a solvent: e.g. polyester and vinylester resins.

Surface hardness
The surface hardness is the measure of the resistance against indentation of a test needle. Important methods are: Shore A, Shore D and the ball indentation hardness.


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