Effect of linear comonomers on the rate of crystallization of copolyesters

Abstract

Small amounts of dimethyl-4,4Ј-biphenyldicarboxylate, 2,7-dimethyl-4,5,9,10-tetrahydropyrenedicarboxylate, and dimethyl-2,7-pyrenedicarboxylate have been copolymerized into poly(ethylene) terephthalate (PET). The thermal transitions of the copolymers have been characterized, and the crystallization rates have been measured isothermally. Avrami analysis indicates that all the copolymers crystallized at a slower rate than that of the PET homopolymer. Addition of perylene to the copolymers containing pyrene enhanced the rate of crystallization, which could be the consequence of stacked arene assemblies serving as templates for crystal formation.

Effect of styrene‐co‐acrylonitrile on cold crystallization and mechanical properties of poly(ethylene terephthalate)

“…Fillers,44, 45 polymers,46, 47 and copolymers48, 49 are added to PET to modify its crystallization behavior. Additives may be used to facilitate (nucleating agents)50–52 or to hinder (antinucleating agents)26, 53, 54 the crystallization of PET. Additives that modify the crystallization characteristics without adversely affecting other properties are particularly valuable.…”

Non‐isothermal cold crystallization kinetics and morphology of PET + SAN blends

“…Compounds used to reduce the crystallization rate of PET are scarce in the literature; examples of these agents are THP comonomer,5 SSBA sodium salt,23 and nanosilica 24. However, in these cases a high amount of the second component had to be added to obtain a reasonable reduction in the crystallization rate, and this high concentration might cause a negative effect in the properties and processabillity of PET.…”

“…It has been shown before that blending PET with other polymers may reduce the rate of crystallization 2–4. Another approach to reduce the tendency of PET to crystallize is to add comonomers in the polymerization reactor, obtaining copolymers 5, 6. However, in all the examples shown above two disadvantages are evident: (i) when copolymers are produced, a change in the polymerization conditions has to be done, resulting in huge implications to the industry procedures, including a reduction in production versatility and an increase in costs; (ii) when blends are prepared, at least in the studies cited earlier, the second component is usually added in reasonably high concentrations—between 10 and 50 wt %, with many implications to mechanical and optical properties and also to processing conditions.…”

Crystallization of 2‐methyl‐1,3‐propanediol substituted poly(ethylene terephthalate). I. Thermal behavior and isothermal crystallization

“…It is important to note, however, that many investigators have found evidence suggesting that copolymerizing PET with certain species actually increases the rate of crystallization. Connor et al3 found that copolymerizing PET with one of three different comonomers (dimethyl‐4–4′‐biphenyldicarboxylate, 2,7‐dimethyl‐4,5,9,10‐tetrahydro‐pyrenedicarboxylate, or dimethyl‐2,7‐pyrenedicarboxylate) reduced the overall rate of crystallization. However, it was found that when perylene was added to the copolymers containing pyrene the rate of crystallization was apparently enhanced.…”