Reactions Occurring during the Melt Mixing of Nylon 6 and Oxazoline−Cyclophosphazene Units

Abstract

Specific reactions of amino and carboxyl end groups of Nylon 6 with the reactive oxazoline groups belonging to a cyclophosphazene compound (referred as CP2OXA) were carried out at 240 °C for different times, under inert atmosphere. Ny6 polymers terminated with one specific reactive chain end (−COOH or NH2) were reacted with different amounts of CP2OXA to study the kinetic order of the reactions. All Ny6−CP2OXA reacted products soluble in trifluoroethanol (TFE) were well characterized by MALDI−TOF MS, FT-IR and (1H and 13C) NMR techniques. The MALDI−TOF results show that the oxazoline rings react with the carboxyl chain ends of Ny6 following second-order kinetics. The reactions with amino chain ends are very fast and high amounts of gels are produced in just 5 min heating, whereas traces of gel are formed when Ny6COOH and CP-2OXA are reacted for 60 min. The gels were characterized by FTIR analyses, and also by MALDI−TOF MS after partial acid hydrolysis. MALDI−TOF mass spectra reveal also that oxazoline rings can react with −NH amide groups along the Ny6 chains, and with secondary amino groups formed by a condensation reaction involving the elimination of ammonia from two amino chain ends. These side reactions could be responsible of the formation of the gels. The polymerization of CP2OXA was also observed, and the oligomers formed could also react with Ny6 samples during the melt mixing.

Mass Spectrometry of Synthetic Polymers

“…In both cases dechlorination products were detected by GC/MS . The melt mixing of Nylon-6 and oxazoline-cyclophosphazene units led to the formation of traces of gel determined by MALDI-TOF-MS after acid hydrolysis . Direct probe-atmospheric pressure chemical ionization (DP-APCI) MS and MS/MS of cross-linked copolymers and copolymer blends (amphiphilic conetworks), (Figure ) were applied to reveal information about the thermal stability of the different domains within the copolymer .…”

Studies on chain extension of a novel bio‐based engineering elastomer using 4,4‐diphenyl methane diisocyanate as a chain extender

“…Chain extension methods have been used on PET, 17,18 PLA, 19 and PBS. 20 The most common chain extenders reported are bi-and multifunctional epoxies, 21 diisocyanates, 22 dianhydrides, 23 bis-oxazolines, 24 diol, and diamine. 25 The multifunctional chain extender usually leads to crosslinking structures of the products, which are not suitable for the secondary processing of rubbers.…”

Processing – morphology – property relationships of polyamide 6/polyethylene blend–clay nanocomposites

“…Blends of polyamides with polyolefins and polyesters are particularly interesting and attractive from an industrial point of view. During the last years, it has been shown that such blends can be efficiently compatibilized with numerous compounds derived from maleic anhydride, acrylic acid, glycidyl methacrylate, oxazoline, etc., grafted onto the polyolefin chain so that hydrogen bonds, or even covalent bonds, can be formed between the two polymers at the blending stage [10][11][12][13][14][15][16][17][18]. Nanocomposites based on polyethylene (PE) and polyamide (PA) blends have also been studied.…”