Crystallization of poly(ethylene terephthalate) modified with codiols

Abstract

The nucleation of poly(ethylene terephthalate) (PET) by codiols and olefinic segments was studied. The codiols 1,5-pentanediol, 1,8-octanediol, 2,5-hexanediol, and 1,3-dihydroxymethyl benzene were copolymerized into PET in a concentration range of 0 -10 mol %. The melting (T m ), crystallization (T c ), and glass-transition (T g ) temperatures were studied. These codiols were found to be able to nucleate PET at low concentrations, probably by lowering the surface free energy of the chain fold. However, the codiols also disturbed the structural order of the polymer, resulting in a decrease in both the T m and T c values. The optimum codiol concentration was found to be at around 1 mol %, which is lower than previously reported. A diamide segment N,NЈ-bis(p-carbomethoxybenzoyl)ethanediamine (T2T) was found to be a more effective nucleator than the codiols; however, no synergy was observed between the nucleating effect of the diamide segment T2T and that of the codiol. An olefinic diol (C 36 -diol) with a molecular weight of 540 g/mol was also copolymerized into PET in a concentration range of 0 -21 wt %. Only one T g was observed in the resulting copolymers, suggesting that the amorphous phases of PET and the C 36 -diol are miscible. The main effect of incorporating the C 36 -diol into PET was the lowering of the T g ; thus, the C 36 -diol is an internal plastifier for PET. The C 36 -diol had little effect on the T m value; however, the T c value actually increased in the 11.5 wt % copolymer. As the T g decreased and the T c increased, the crystallization window also increased and thereby the likelihood of crystallization. Therefore, the thermally stable C 36 -diol appears to be an interesting compound that may be useful in improving the crystallization of PET.

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

“…Of notable applicability to the present study, Bier et al5 found that PET copolymers containing ∼5 mol % of branched codiols, such as 2,5‐hexanediol and 3‐methyl‐2,4‐pentanediol, crystallized significantly more rapidly than PET homopolymer. In a related study, Bouma et al6 found that PET copolymers containing low concentrations of 1,5‐pentanediol, 1,8‐octanediol, 2,5‐hexanediol, or 1,3‐dihydroxymethyl benzene were able to enhance nucleation. Bouma et al6 found the optimum concentration of 2,5‐hexanediol to be 1 mol %, much lower than that suggested by Bier et al5 Likewise, it was shown that copolymers containing a branched olefinic diol (C 36 ‐diol) were also able to improve crystallizability.…”

Preparation and characterization of poly(ethylene terephthalate) copolyesters modified with sodium‐5‐sulfo‐bis‐(hydroxyethyl)‐isophthalate and poly(ethylene glycol)

“…Poly(ethylene terephthalate) (PET) is widely used in many domains of synthetic fibers, liquid containers, thermoforming plastics, engineering resins, and textile and apparel industry [1][2][3][4] because of its superior properties such as better elasticity, higher strength, thermal stability, and other advantages. [5][6][7] However, some disadvantages of PET fibers such as low moisture regain, poor dyeability and antistatic property, rigid, and waxy handling [8][9][10] are mainly involved by the high regularity of molecular chains, high crystallinity, and low hydrophilicity, 11,12 which are hindering their further application in textile, fashion, and other industries.…”

Isothermal crystallization and melting behavior of 2‐methyl‐1,3‐propanediol substituted sulfonated poly(ethylene terephthalate) copolyesters

“…Poly(ethylene terephthalate) (PET) has many outstanding properties for textile and industrial fiber applications, but it is difficult to dye because of its high crystallinity, marked hydrophobicity, and lack of chemically active groups 1–5. It is well known that copolymerization of polyesters with ionic groups constitutes a very effective method to improve both chemical and physical properties of the polymer 6, 7.…”