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.

    Our team are available from 8am-5pm and we always aim to get back to you the same day. If you would rather contact us immediately please join us on live chat or give us a call on 0141 952 1900.

    < Back to home

    What can imide links do that amide cannot?

    Polymers with amide links have been around for some time but the close cousins, the imide links, are less well known.  The original polyimides, first synthesised over 60 years ago, offered some amazing high temperature performance up to 300oC but could be processed only by sintering, to produce film (‘Kapton’) and rod (‘Vespar’), which greatly limited their applications.

    Spectacles imide links

    To produce a material that could be extruded or injection moulded, links with more ‘molecular flexibility’ had to be introduced. This was in order to reduce the melt processing temperature to manageable levels.  The most successful member of the imide family is polyetherimide (PEI). It incorporates ether links, which has high stiffness and strength and a heat distortion temperature in excess of 200oC, even without reinforcing filler.  The bonus is that PEI is amorphous and hence transparent.  Few thermoplastics can match the combination of transparency and high temperature performance.

    The other contributions from the imide links are hydrocarbon resistance, good fire performance, interesting electrical properties, weathering resistance, stress crack resistance and low mould shrinkage. These lead to diverse applications in the automotive, electronics and medical markets.  Perhaps not as high tech as some applications but the tough, lightweight spectacle frames appeal to me.

    Although resistant to hydrocarbon solvents, alcohol and water, PEI is attacked by alkali and chlorinated solvents.  PEI also requires high processing temperatures (over 350oC), high mould temperatures and predrying.

    Trade names: ‘Ultem’

    Search results

    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.

    Read more >

    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.

    Read more >

    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.

    Read more >

    What makes medical grade plastics so special?

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

    Read more >

    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.

    Read more >

    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.

    Read more >

    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.

    Read more >

    Where are Engineering Thermoplastics Blends going ?

    The timeline of appearance of materials for the plastics industry can be viewed as several overlapping phases.

    Read more >

    Understanding the difference between SBS & SEBS thermoplastic elastomers?

    The difference between SBS and SEBS thermoplastic elastomers explained.

    Read more >

    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.

    Read more >