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Synthesis, characterization, and mechanical properties of an injection moldable polyimide based on 1,4‐diaminobutane
Author(s) -
Koning Cor,
Teuwen Liliane,
Bulters Markus
Publication year - 1996
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10529
Subject(s) - materials science , polyimide , tetrahydrofuran , branching (polymer chemistry) , ultimate tensile strength , composite material , polymer chemistry , small angle x ray scattering , molding (decorative) , dynamic mechanical analysis , modulus , izod impact strength test , thermosetting polymer , polymer , solvent , scattering , organic chemistry , chemistry , physics , layer (electronics) , optics
A partially aliphatic polyimide was synthesized in a two‐step process in N‐methylpyrrolidone (NMP) from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and 1,4‐diaminobutane (DAB). Weight average molecular weights ranging from 35,000 to over 160,000 were obtained by adding different amounts of the chain stopper phthalic anhydride, or by using a slight excess of BTDA. Rheological measurements, supported by a size exclusion chromatography (SEC) analysis before and after injection molding, point to branching or even partial crosslinking during molding of poly(BTDA‐DAB) if reactive amine endgroups are present. By reacting these amine endgroups with benzoyl chloride, branching is limited and a more Newtonian flow is observed. Both non‐endcapped and endcapped reactor powders are ∼60% crystalline ( Tg = 170 to 175°C, Tm = 290 to 300°C), but according to wide and small angle X‐ray scattering (WAXS and SAXS) studies on test bars, both the more linear polyimides and their branched counterparts are fully amorphous after injection molding. Nevertheless, poly(BTDA‐DAB) shows interesting mechanical properties like a bending modulus of ∼3.9 GPa, a tensile strength of ∼130 MPa, a tensile elongation at break of ∼13%, and a notched Izod impact of ∼4 kJ/m 2 .