Structure and basic properties of aminated PET

Abstract

SYNOPSISThe triethylenetetramine (TETTA) surface-modification process for fibers, consisting of short-time annealing and high-temperature treating the fibers previously padded in TETTA, has been developed. The annealing (60 s, 1'70°C) of the fibers was performed to restrict the reaction on the surface. To characterize the structure and properties of TETTA-modified fibers, IR spectroscopy, DSC, and X-ray diffraction were applied and critical dissolution time, dye uptake, density, and basic physical-mechanical properties were determined. It was shown that after annealing and aminolysis of the fibers Tg increases to 115"C, while the crystallinity index (determined by DSC) is changed from 33 to 46% (X-ray crystallinity increased from 47 to 59%) and critical dissolution time increased from 12.9 to 58.9 min, depending on the time of aminolysis. The results obtained suggested the existence of two simultaneous processes during the aminolysis: macromolecular scission responsible for introducing the amine groups at the surface and partial crystallization of PET. INTRODUCTIONThe properties of composites are often tailored by fiber hybridization. Thus, the impact resistance of C fiber-reinforced epoxy matrix composites can be increased by incorporating organic fibers, such as P E T and PE, into the composite structure, without noticeably damaging the other basic mechanical properties of the composite material (CM).' However, the interface fiber/matrix adhesion in hybrid composites is still among the key factors influencing the overall composite properties. Therefore, being extremely inert, PE, PET, and other organic fibers used as reinforcements in the CM usually undergo different surface modification prior use.Among the methods of modification, fiber-surface activity, low-temperature plasma treatment, as well as chemical modification with low molecular weight compounds are often applied to increase the compatibility toward and adhesion to common polymer matrices.' In our previous work,3 surface-aminated PET fibers were used in C fiberlepoxy resin com-* To whom correspondence should be addressed.Journal of Applied Polymer Science, Vol. 62, 605-612 (1996) TETTA was shown to be quite efficient, it seems too difficult to be accepted for industrial scale. T o simplify the surface-modification process, a twostage procedure was developed, consisting of shorttime annealing and then high-temperature treating of the fiber with TETTA, as described in detail elsewhere.5 I t was previously established t h a t under the proposed conditions the reaction with T E T T A occurs exclusively in the thin surface layer of the fiber via a macromolecular scission mechanism.This present article deals with the basic parameters of t h e structure and properties of aminated PET fibers. EXPERIMENTAL MaterialsThe polyester fabric cloth used was in the form of filament woven fabric cloth made from filament yarns of dtex 140, 48 filaments, and 150 twist. Threads per cm for the fabric were 25 in ends and 24 in picks. All chemicals were of reagent gra...

Characterization of PET films modified by tetraethylenepentamine (TTEPA)

“…10 It should be noted that the N content refers to atoms available for protonation and may not reflect the total N content of the sample. Films were titrated immediately after drying to maximize the number of N atoms that could be protonated.…”

The effect of xylene as aromatic solvent to aminoglycolysis of post consumer PET bottles

“…Aminolytic modification reactions of PET fibers were carried out using primary amines such as methylamine , ethylamine , and butylamine in aqueous solutions. In addition, there are few studies about used other amines such as ethanolamine and triethylenetetramine . The rate of degradation of PET is determined by the steric hindrance and basicity of amine .…”

Chemical Recycling of PET: Methods and Products

“…The processes of a partial surface modification of PET fibers or powders by aminolysis have been the subject of extensive research [114,[132][133][134][135][136][137][138][139] and find industrial-scale application. Such modification processes improve the dyeability and other technical and end-use parameters of the fibers.…”

“…In most cases, the aminolytic modification of PET fiber surfaces is conducted using primary amines in aqueous solutions [114,[132][133][134][135][136][137][138][139] or, less frequently, in gaseous form [138]. Most frequently used are methylamine [133][134][135][136], ethylamine [114,136], and butylamine [114,137].…”

“…Most frequently used are methylamine [133][134][135][136], ethylamine [114,136], and butylamine [114,137]. Ethanolamine [136], ethylene diamine [139], and triethylene tetramine [138] are also used. The purpose of this aminolytic PET fiber modification is a selective degradation, allowing control of the fiber morphology.…”