Uncrosslinked epoxide‐amine addition polymers, 44. Linear arylamine/2,2‐bis[4‐(2,3‐epoxypropoxy)phenyl]‐propane addition polymers — synthesis and properties

Abstract

The addition polymerization of aromatic disecondary diamines and 2,2-bis[4-(2,3-epoxypropoxy)phenyl]propane (DGEBA) leads to linear high molecular weight epoxideamine addition polymers with number-average molecular weights ranging from 10000 to 20000 g/mol. Depending on the amine structure, their glass transition temperatures were estimated between 80 and 140°C. The fractionation of the high molecular weight addition polymers allows the separation of cyclic --oligomers and the separation of polymers with narrow molecular weight distribution (MJM,, = 2.4-2.8). In dilute solution, predominantly cyclic oligomers were formed. Hence, they were prepared in such solutions and isolated by means of column chromatography. Their cyclic structure is proved by combination of a values and I3C NMR spectra.

Linear Addition Polymers and Cyclic Oligomers ofN,N-Diglycidyl Aniline and Amines. Uncrosslinked Epoxide-Amine Addition Polymers, 46

“…[6] Aniline, benzylamine, 1-aminoadamantane and DGA, received from Fluka (Buchs, Switzerland), were distilled in vacuum before use.…”

“…[8] Small amounts of series of cyclic oligomers were also found in linear epoxide-amine addition polymers of DGEBA and primary monoamines, [9,10] which were separated by precipitation of addition polymers in acetone. [6,7] Some years ago the formation of cyclic oligomers of DGEBA and primary monoamines seemed to be impossible because of the assumed high ring tension. [11,12] The question is how rigid must be a molecule be in order to avoid cyclization?…”

Molecular weight effects on the mechanical properties of novel epoxy thermoplastics

“…Very high molecular weight epoxy thermoplastics (ETPs), greater than 10 times the entanglement molecular weight (M e ), are traditionally difficult to synthesize for a series of reasons, foremost being the fact that side reactions such as the formation of cyclic oligomers [19][20][21] are common, especially in reactions performed in dilute solutions, 19 while etherification occurs primarily at high reaction temperatures. 19,22 Solution polymerization poses problems when accurate determination of mechanical properties is necessary in composite materials as the residual solvent(s) often plague the data by acting as a plasticizer and altering bulk properties. Consequently, such polymers have been synthesized only on a narrow and limited basis, often with high degrees of branching and broad polydispersity.…”

“…Renner and Michaelis advanced a DGEBA-based epoxy oligomer using aliphatic and aromatic difunctional amines with and without solvent to obtain ETPs of number average molecular weights (M n ) in the range of 9 500-33 300 g mol À1 . 22 Klee and coworkers employed secondary diamines to advance a DGEBA epoxy oligomer in dilute 19 and concentrated 20 solutions to yield linear epoxies with M n values between 8000 and 18 000 g mol À1 . Blanco et al reacted a DGEBA-based epoxy oligomer with p-toluidine to obtain an ETP with M n of 19 400 g mol À1 .…”