Since polycondensation polyimide has the disadvantages as mentioned above, in order to overcome these disadvantages, polymerisation polyimide has been developed. The main ones that have gained wide application are polybismaleimide and norbornene-based end-capped polyimides. Usually, these resins are low relative molecular mass polyimides with unsaturated groups at the ends, and then polymerised by unsaturated end groups when applied.
①Polybismaleimide
Polybismaleimide is made by polycondensation of maleic anhydride and aromatic diamine. Compared with polyimide, its performance is not bad, but the synthesis process is simple, easy post-processing, low cost, can be easily made into a variety of composite products. But the cured material is more brittle.
②Norbornene-based capped polyimide resin
One of the most important is developed by NASA Lewis Research Center, a class of PMR (for insitu polymerization of monomer reactants, monomer reactants in situ polymerization) type polyimide resins. RMR-type polyimide resins are aromatic tetracarboxylic acid dialkyl ester, aromatic diamine and 5-norbornene-2, 3-dicarboxylic acid monoalkyl ester, aromatic diamine and 5-norbornene-2, 3-dicarboxylic acid monoalkyl esters. 3-dicarboxylic acid monomers such as dialkyl esters of aromatic tetracarboxylic acids, aromatic diamines and monoalkyl esters of 5-norbornene-2,3-dicarboxylic acid are dissolved in a tasted alcohol (e.g., methanol or ethanol) to produce a solution that can be used directly to impregnate fibres. Polyimide is a molecular structure containing imide-based chain links of aromatic heterocyclic polymer compounds, the English name Polyimide (referred to as PI), can be divided into benzene-type PI, soluble PI, polyamide-imide (PAI) and polyetherimide (PEI) four categories.
Extended Reading：
PC-37 – Amine Catalysts (newtopchem.com)
Dabco foaming catalyst/polyurethane foaming catalyst NE300 – Amine Catalysts (newtopchem.com)
DABCO EG/PC CAT TD 33EG/Niax A-533 – Amine Catalysts (newtopchem.com)
FASCAT4100 catalyst – Amine Catalysts (newtopchem.com)
T120 1185-81-5 di(dodecylthio) dibutyltin – Amine Catalysts (newtopchem.com)
DABCO 1027/foaming retarder – Amine Catalysts (newtopchem.com)
DBU – Amine Catalysts (newtopchem.com)
bismuth neodecanoate/CAS 251-964-6 – Amine Catalysts (newtopchem.com)
stannous neodecanoate catalysts – Amine Catalysts (newtopchem.com)
polyurethane tertiary amine catalyst/Dabco 2039 catalyst – Amine Catalysts (newtopchem.com)