Please note that we only supply polymer in granular form for Injection Moulding or Extrusion applications. We do not supply polymer in rod, sheet or block form.

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    Thermoplastics and UV: Friend or Foe?

    Thermoplastics and UV: Radiation in the ultraviolet region of the spectrum is a bit of a mixed blessing for polymers.

    PLASTIC_CHAIR Thermoplastics and UV

    Over 50 years ago, polymer chemists harnessed UV radiation energy in the laboratory to initiate and control radical chain addition polymerisation, thereby working out the kinetics for large scale commercial polymerisation initiated mostly by peroxides.

    Today UV initiation is used to polymerise acrylates in dental materials.  Ask your dentist for more details next time you have an appointment.  We are also hearing more about the role of UV initiated polymerisation in self-healing composites.

    On the other hand the high energy associated with UV can do serious damage to thermoplastics.   Polymer chain scission can cause loss of mechanical properties; cross linking reactions can lead to embrittlement and also other reactions result in discoloration.

    I am old enough to remember the excitement of the first injection moulded polypropylene chairs.  One consignment found its way to a golf club on the slopes of Mt Kilimanjaro, only to disintegrate several months later because nobody had told the materials supplier about the excessive UV exposure to which the chairs would be subjected.

    Fortunately today we have an excellent range of UV stabilisers to call upon to prevent such a scenario but designers of products for outdoor exposure should always double check that the selected grade of thermoplastic is up to the challenge.

    Finally, more information on this topic may be available on the excellent British Plastics Federation website.

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    Coping with weld lines

    In injection moulding, weld lines (knit lines) form when two melt fronts meet. If the melt fronts do not coalesce completely, at best there will be a cosmetic flaw. At worst there will be a mechanical weak-spot, with strengths of the order of 10 - 90 % of the material potential.

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    What determines friction between thermoplastic components?

    Friction is an important property for thermoplastics in bearings and gears but also has a part to play in assembly of plastic parts (snap-fit and interference-fit) and ejection during moulding.

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    Polypropylene: the Workhorse of the Plastics Industry

    Polypropylene. Little did Karl Zeigler or Giulio Natta realise, 60 years ago, when they were developing a catalyst system to produce a useful thermoplastic from the inexpensive monomer, propylene, that their work would have such far reaching consequences.

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    What makes medical grade plastics so special?

    Toughness and transparency are important properties for the constituents of intravenous lines.

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    The Long and the Short of Fibre Reinforcement of Thermoplastics

    Fibre Reinforcement. The advantages of adding glass fibre to thermoplastics to increase stiffness (modulus), strength, heat distortion resistance and dimensional stability are well known.

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    What causes mouldings (and moulders) to be off-colour?

    When mouldings are not the intended colour, the first thing to check is the raw material, particularly the dosing rate, if you are using masterbatch, and the quality of regrind.

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    Transparent ABS can be a clear winner

    Transparent ABS. Mentioning transparency in the context of ABS moulding materials can raise a few eyebrows. This is because ABS is normally taken to be opaque and indeed the vast majority of grades of ABS are opaque.

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    Understanding the difference between SBS & SEBS thermoplastic elastomers?

    The difference between SBS and SEBS thermoplastic elastomers explained.

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    Is MFR really much help to moulders these days ?

    Often a moulder has to change material grades. One of the first properties to be consulted on the new data sheet is usually the MFR. This is to establish if the new grade has the same melt viscosity performance.

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    What gives Moulders a Warped View on Life?

    Warping is one of the most frustrating injection moulding faults. This is because it does not always appear immediately, the causes are complex and prevention is difficult.

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