Characterization and crystallization behavior of poly(ethylene‐co‐trimethylene terephthalate) copolymers

A series of poly(ethylene‐co‐trimethylene terephthalate) (PETT) copolymers were prepared by polycondensation. The synthesized PETT are block copolymers and the content of poly(trimethylene terephthalate) (PTT) units incorporated into the copolymers are always larger than that fed in the polymerization. The nonisothermal crystallization at the different cooling rates was studied by means of differential scanning calorimetry. The copolymers develop the crystallization later and show the lower melting temperature than the corresponding enriched homopolymers. The modified Avrami analysis fit well the nonisothermal crystallization of these polymers. The overall rate of crystallization of PTT is fastest and that of PET is slowest, whereas the copolymers are between them at the same cooling rate. The minor PET units incorporated into PTT polymer chains reduce the crystallization of PTT segments, but the present minor PTT units in the PET chains seem to accelerate the crystallization of PET segments. The Avrami exponent nvaries in the range of 3 – 4, indicating that the nonisothermal crystallization follows the homogeneous nucleation and two‐ to three‐dimensional growth mechanism. Wide angle X‐ray diffraction analysis explains that the PET and PTT units do not cocrystallize and it is considered as the enriched polymer segments to crystallize during crystallization. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Crystallization behavior and crystal structure of poly(ethylene‐co‐trimethylene terephthalate)s

A series of random copolymers were synthesized by the bulk polycondensation of dimethyl terephthalate with ethylene glycol (EG) and propane‐1,3‐diol (PDO) in various compositions. Their composition and thermal properties were investigated. The copolymers with 57.7 mol % or more PDO or 14.4 mol % or less PDO were crystallizable, but those with 36–46.2 mol % PDO were amorphous. The nonisothermal crystallization behavior was investigated with varying cooling rates by DSC. Poly(ethylene terephthalate) (PET) and poly(trimethylene terephthalate) (PTT) homopolymers have relatively lower activation energy than their copolymers. PET‐rich copolymers (EG > 85.9%) exhibited PET crystal structure, and exhibited no PTT crystal structure; and PTT‐rich copolymers (PDO > 41.7%) exhibited PTT crystal structure, and exhibited no PET crystal structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Structural investigation of Poly(ethylene terephthalate)/Poly(trimethylene terephthalate) transesterificated blends

Wide-Angle X-ray Diffraction (WAXD) and Small-Angle X-ray Scattering analyses were carried out to evaluate the evolution of the crystalline and supermolecular structure of poly(ethylene terephthalate) (PET) blended with poly(trimethylene terephthalate) (PTT). The conditions adopted in preparing the PET/PTT 50/50 blend induce transesterification between the polyesters; these reactions produce a new molecular characteristics based on PET/PTT copolymer that exhibits its own WAXD profile. The PET/PTT 50/50 copolymers prepared by melt mixing of the homopolymers for increasing times evidence spherulitic morphology and an evolution of the crystalline structure in terms of crystallinity and crystal dimensions. The periodicity of the transesterificated samples is intermediate between the long periods observed for pure PET and pure PTT. For the PET/PTT 50/50 copolymers the value of periodicity and lamellar thickness increase with the increasing of the processing time.     

Synthesis and properties of poly(trimethylene terephthalate‐co‐2‐methyl‐ethylene terephthalate) random copolyesters

Poly(trimethylene terephthalate‐co‐2‐methyl‐ ethylene terephthalate) random copolymers of various compositions were synthesized via traditional two‐step polycondensation by incorporating of 1,2‐propanediol. The molar composition of trimethylene terephthalate and 2‐methyl‐ethylene terephthalate units and chemical structure were confirmed by means of ¹H‐NMR and Fourier transform infrared. The thermal properties of the copolyesters were evaluated by DSC and TGA. As far as the thermal properties is concerned, the main effect of incorporation of 1,2‐propanediol was a lowering in the melting temperature, and an increment of glass transition temperature compared to homopolymer PTT. Due to the effect of the lateral methyl groups in the polymeric chain, the thermal stability is slightly decreased as the amount of the MET units is increased. Furthermore, the crystals of PTT/MET copolyesters were observed by hot‐stage optical polarizing microscopy at the indicated crystallization temperatures. As expected, the incorporation of MET units in the polymer chain of PTT was found to decrease the dimension of the crystals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Molecular structures and physical properties of heat‐drawn conjugate fibers

As‐spun poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) side‐by‐side conjugate fibers were drawn to investigate the effects of drawing conditions on structure development and physical properties. Effects of draw ratio and heat‐set temperature were observed. In the state of an as‐spun fiber, the molecular orientation of PTT was higher than PET, whereas PET molecular orientation increased remarkably over PTT with increasing draw ratio. Crimp contraction increased sharply at a draw ratio over 2.0, where the crystalline structure of the PET developed sufficiently. A heat‐set temperature of at least 140°C was required to develop sufficient crimp contraction. The crystallinity and orientation of the PET were attributed mainly to the crimp contraction of the drawn fiber. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Sequence distribution,thermal properties,and crystallization studies of poly(trimethylene terephthalate‐co‐1,4‐cyclohexylene dimethylene terephthalate) copolyesters

A series of novel poly(trimethylene terephthalate‐co‐1,4‐cyclohexylene dimethylene terephthalate) (PTCT) with various compositions were synthesized by melt polycondensation of 1,3‐propanediol, 1,4‐cyclohexanedimethanol and dimethyl terephthalate. The resulting copolyesters were characterized using ¹³C and ¹H nuclear magnetic resonance. The average length of both trimethylene terephthalate (TT) and cyclohexylene dimethylene terephthalate (CT) sequences varies from 1 to 10, and the chain structure is statistically random. The crystallization was investigated using wide angle X‐ray diffractometer (WAXD) and differential scanning calorimeter. The WAXD patterns can be divided in two groups according to the composition: copolyesters with less than 35 mol % CT content exhibit PTT‐type lattice, and those with CT unit content higher than 42 mol % crystallize with the PCT‐type lattice. The crystallizability of CT sequence is higher than that of TT sequence. Thermodynamic analysis shows that the comonomer is excluded from the PTT‐type or PCT‐type crystal of the copolyesters. The thermal decomposition temperature of copolyesters increases with increasing CT content, and their thermal stability is improved as compared to that of PTT. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Structure–property evolution of poly(ethylene terephthalate)/poly(trimethylene terephthalate) side-by-side self-crimp filament

To investigate the microstructure and mechanical properties of self-crimping two-component side-by-side bicomponent filament, this paper focuses on systematically investigating the structure–property evolution of poly(ethylene terephthalate) (PET)/poly(trimethylene terephthalate) (PTT) side-by-side bicomponent filament prepared via melt spinning with various component ratios, drawing and heating treatment. The investigation was operated upon the combination of morphology analysis, thermal analysis, crystallization, and orientation analysis. The variation of cross section and curl-morphology, crystallization, and microstructures mainly containing lamellar and microfibrillar crystals as well as their effects on the mechanical and self-crimping properties were discussed. As the draft ratio (DR) increases, the crystallinity, sonic orientation factor, tensile strength, and crimp-recovery rate of the filaments were increased. The sonic orientation factor in the crystalline region decreases from 0.923 to 0.777 but increases from 0.677 to 0.903 in the amorphous region. In contrast to the variation of the DR, heating temperature has a limited effect on the tensile strength of the PET/PTT hybrid filaments. Crimp-recovery rate, however, first increases to 11.8 and then decreases to 9.8 with an increasing heating temperature from 144 to 168°C. Most of these behaviors have been attributed to changes in the ratio of contractile stress for both PTT and PET components, originating from microstructural evolution in hybrid filaments, including crystal growth, breakage, deflection, and deformation of chains along the axial direction. As a summary, an interpretive diagrammatic sketch has been proposed to clarify the structure–property relationships of the commercial PET/PTT filaments.     

Poly(trimethylene terephthalate‐block‐tetramethylene oxide) elastomer/single‐walled carbon nanotubes nanocomposites: Synthesis,structure, and properties

Nanocomposites based on poly(trimethylene terephthalate)‐block‐poly(tetramethylene oxide) (PTT‐PTMO)‐segmented copolymer and COOH‐functionalized single‐walled carbon nanotubes (SWCNTs) were prepared by in situ polymerization method. The obtained nanocomposites were characterized by thermogravimetric analysis, scanning electron microscopy, differential scanning calorimetry (DSC), DMTA, wide‐angle x‐ray scattering (WAXS), small‐angle X‐ray scattering, and tensile testing. The nanocomposites with low SWCNTs loading (<0.5 wt %) shows uniform dispersion of CNT in polymer matrix. As the SWCNTs loading in the nanocomposites increase, the significant improvement of thermo‐oxidative stability was observed. It was found that the nanocomposites have slightly higher degree of crystallinity (determined by DSC and WAXS) of poly(trimethylene terephthalate) (PTT) hard phase than neat PTT‐PTMO copolymer. The melting point of PTT hard phase and glass transition temperature of poly(tetramethylene oxide)‐rich phase were not affected by the presence of CNTs in polymer matrix. The SWCNTs played a role as nucleating agent in PTT‐PTMO matrix, which led to increase in the crystallization rate. Tensile tests showed that the tensile strength of the nanocomposites with 0.05–0.3 wt % loading of SWCNTs have improved tensile strength in comparison to the neat PTT‐PTMO copolymer without reduction elongation at break. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Antielectrostatic poly(ether ester) block copolymer of poly(ethylene terephthalate‐co‐isophthalate)–poly(ethylene glycol)

Poly(ethylene terephthalate) (PET) fiber has a low moisture regain, which allows it to easily gather static charges, and many investigations have been carried out on this problem. In this study, a series of poly(ethylene terephthalate‐co‐isophthalate) (PEIT)–poly(ethylene glycol) (PEG) block copolymers were prepared by the incorporation of isophthalic acid (IPA) during esterification and PEG during condensation. PEG afforded PET with an increased moisture affinity, which in turn, promoted the leakage of static charges. However, PET also then became easier to crystallize, even at room temperature, which led to decreased antistatic properties and increased manufacturing inconveniences. IPA was, therefore, used to reduce the crystallinity of the copolymers and, at the same time, make their crystal structure looser for increased water absorption. Moreover, PET fibers with incorporated IPA and PEG showed good dyeability. In this article, the structural characterization of the copolymers and antistatic and mechanical properties of the resulting fibers are discussed. At 4 wt % IPA, the fiber containing 1 mol % PEG with a molecular weight of 1000 considerably improved antistatic properties and other properties. In addition, the use of PEIT–PEG as an antistatic agent blended with PET or modified PET fibers also benefitted the antistatic properties. Moreover, PEIT–PEG could be used with another antistatic agent to produce fibers with a low volume resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1696–1701, 2003     

Reactive blending of aromatic polyesters: Thermal and X‐ray analysis of melt‐blended poly(ethylene terephthalate)/poly(trimethylene terephthalate)

We investigated the reactive melt blending of poly(ethylene terephthalate) (PET) and poly(trimethylene terephthalate) (PTT) in terms of the thermal properties and structural features of the resultant materials. Our main objectives were (1) to investigate the effects of the processing conditions on the nonisothermal melt crystallization and subsequent melting behavior of the blends and (2) to assess the effects of the blending time on the structural characteristics of the transreaction products with a fixed composition. The melting parameters (e.g., the melting temperature, melting enthalpy, and crystallization temperature) decreased with the mixing time; the crystallization behavior was strongly affected by the composition and blending time. Moreover, a significant role was played by the final temperature of the heating treatment; this meant that interchange reactions occurred during blending and continued during thermal analysis. The wide‐angle X‐ray diffraction patterns obtained under moderate blending conditions showed the presence of crystalline peaks of PET and PTT; however, the profiles became flatter after blending. This effect was more and more evident as the mixing time increased. Transesterification reactions between the polyesters due to longer blending times with an intermediate composition led to a new copolymer material characterized by its own diffraction profile and a reduced melting temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Crystallization kinetics of poly(1,4‐butylene‐co‐ethylene terephthalate)

The crystallization kinetics of poly(butylene terephthalate) (PBT), poly(ethylene terephthalate) (PET), and their copolymers poly(1,4‐butylene‐co‐ethylene terephthalate) (PBET) containing 70/30, 65/35 and 60/40 molar ratios of 1,4‐butanediol/ethylene glycol were investigated using differential scanning calorimetry (DSC) at crystallization temperatures (T_c) which were 35–90 °C below equilibrium melting temperature . Although these copolymers contain both monomers in high proportion, DSC data revealed for copolymer crystallization behaviour. The reason for such copolymers being able to crystallize could be due to the similar chemical structures of 1,4‐butanediol and ethylene glycol. DSC results for isothermal crystallization revealed that random copolymers had a lower degree of crystallinity and lower crystallite growth rate than those of homopolymers. DSC heating scans, after completion of isothermal crystallization, showed triple melting endotherms for all these polyesters, similar to those of other polymers as reported in the literature. The crystallization isotherms followed the Avrami equation with an exponent n of 2–2.5 for PET and 2.5–3.0 for PBT and PBETs. Analyses of the Lauritzen–Hoffman equation for DSC isothermal crystallization data revealed that PBT and PET had higher growth rate constant G_o, and nucleation constant K_g than those of PBET copolymers. © 2001 Society of Chemical Industry     

Melt spinning and drawing of 2‐methyl‐1,3‐propanediol‐substituted poly(ethylene terephthalate)

The structure and properties of fibers prepared from copolymers of poly(ethylene terephthalate) (PET) in which 2‐methyl‐1,3‐propanediol (MPDiol® Glycol is a registered trademark of Lyondell Chemical Company) at 4, 7, 10, and 25 mol% was substituted for ethylene glycol were studied and compared with those of PET homopolymer. Filaments were melt spun over a range of spinning conditions, and some filaments that were spun at relatively low spinning speeds were subjected to hot drawing. The filaments were characterized by measurements of birefringence, differential scanning calorimetry (DSC) crystallinity, melting point, glass transition temperature, wide‐angle X‐ray diffraction patterns, boiling water shrinkage, tenacity, and elongation to break. Filaments containing 25 mol% MPDiol did not crystallize in the spinline at any spinning speed investigated, whereas the other resins did crystallize in the spinline at high spinning speeds. However, compared with PET homopolymer, increasing substitution of MPDiol reduced the rate at which the crystallinity of the melt spun filaments increased with spinning speed and reduced the ultimate crystallinity that could be achieved by high‐speed spinning. The rate of development of molecular orientation, as measured by birefringence, also decreased somewhat with increasing MPDiol content. Shrinkage in boiling water decreased at high spinning speeds as the amount of crystallinity increased; however, the shrinkage decreased more slowly with increase in spinning speed as MPDiol content increased. Tenacity also decreased slightly at any given spinning speed as MPDiol content increased, but there was no significant effect on elongation to break. The addition of MPDiol in amounts up to 7 mol% increased the maximum take‐up velocity that could be achieved at a given mass throughput. This result indicates that the use of higher spinning speeds could potentially increase the productivity of melt spun yarns. Copolymer filaments spun at low speeds were readily drawn to produce highly oriented fibers with slightly less birefringence, crystallinity, and tenacity than similarly processed PET homopolymer. Preliminary dyeing experiments showed that the incorporation of MPDiol improved the dyeability of the filaments. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2598–2606, 2003     

Thermal and crystallization characteristics of poly(ethylene terephthalate) with poly(oxybenzoate‐p‐trimethylene terephthalate) copolymer

Poly(ethylene terephthalate) (PET) was blended with two different poly(oxybenzoate‐p‐trimethylene terephthalate) copolymers, designated T28 and T64, with the level of copolymer varying from 1 to 15 wt %. All samples were prepared by solution blending in a 60/40 (by weight) phenol/tetrachloroethane solvent at 50°C. The crystallization behavior of the samples was studied by DSC. The results indicate that both T28 and T64 accelerated the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of PET crystallization rate was most pronounced in the PET/T64 blends with a maximum level at 5 wt % of T64. The melting temperatures for the blends are comparable to that of pure PET. The observed changes in crystallization behavior are explained by the effect of the physical state of the copolyester during PET crystallization as well as the amount of copolymer in the blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1599–1606, 2002     

Instantaneous elastic recovery of poly(trimethylene terephthalate) filament

The instantaneous elastic recoveries of poly(trimethylene terephthalate) (PTT), PET, and PBT filaments were comparatively analyzed by a tensile testing machine. The conditions of the measurement were studied and the mechanism of instantaneous elastic recovery of these three aromatic polyester filaments is discussed. The instantaneous elastic recovery of PTT filaments was significantly higher than those of PBT and PET filaments. Moreover, PTT filaments had a high instantaneous elastic recovery even at a high elongation of 20%. The outstanding instantaneous elastic recovery of PTT filaments resulted from its helical conformation in crystal lattice, which responded immediately to the applied stress and deformed as though it was a coiled spring; we suggest it was a quasispring elastic recovery mechanism. When we measured the instantaneous elastic recovery of, PTT filaments with the tensile testing machine, it was appropriate to set up the crosshead speed at 500 mm/min with an elongation of 20% and a load of 0.5 cN/tex. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1967–1975, 2004     

Crystallization,morphology, and electrical properties of bio‐based poly(trimethylene terephthalate)/poly(ether esteramide)/ionomer blends

Bio‐based poly(trimethylene terephthalate) (PTT) and poly(ether esteramide) (PEEA) blends were prepared by melt processing with varying weight ratios (0–20 wt %) of ionomers such as lithium‐neutralized poly(ethylene‐co‐methacrylic acid) copolymer (EMAA‐Li) and sodium‐neutralized poly(ethylene‐co‐methacrylic acid) copolymer (EMAA‐Na). The blends were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscopy (PLM), and transmission electron microscopy (TEM). DSC and PLM results showed that EMAA‐Na increased the crystallization rate for PTT significantly, whereas EMAA‐Li did not enhance the crystallization rate at all. Specific interactions between PEEA and ionomers were confirmed by DSC and TEM. Electrostatic performance was also investigated for those PTT blends because PEEA is known as an ion‐conductive polymer. Here, we confirmed that both sodium and lithium ionomers work as a synergist to enhance the static decay performance of PTT/PEEA blends. Morphological study of these ternary blends systems was conducted by TEM. Dispersed ionomer domains were encapsulated by PEEA, which increases the interfacial surface area between PEEA and the PTT matrix. This encapsulation effect explains the unexpected synergy for the static dissipation performance on addition of ionomers to PTT/PEEA blends. This core–shell morphology can be predicted by calculating spreading coefficient for the ternary blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polymer blends of poly(trimethylene terephthalate) and polystyrene compatibilized by styrene‐glycidyl methacrylate copolymers

The compatibilizing effects of styrene‐glycidyl methacrylate (SG) copolymers with various glycidyl methyacrylate (GMA) contents on immiscible blends of poly(trimethylene terephthalate) (PTT) and polystyrene (PS) were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and ¹³C‐solid‐state nuclear magnetic resonance (NMR) spectroscopy. The epoxy functional groups in the SG copolymer were able to react with the PTT end groups (? COOH or ? OH) to form SG‐g‐PTT copolymers during melt processing. These in situ–formed graft copolymers tended to reside along the interface to reduce the interfacial tension and to increase the interfacial adhesion. The compatibilized PTT/PS blend possessed a smaller phase domain, higher viscosity, and better tensile properties than did the corresponding uncompatibilized blend. For all compositions, about 5% GMA in SG copolymer was found to be the optimum content to produce the best compatibilization of the blend. This study demonstrated that SG copolymers can be used efficiently in compatibilizing polymer blends of PTT and PS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2247–2252, 2003     

Synthesis and characterization of poly(ethylene‐co‐trimethylene terephthalate)s

Taking advantage of a melt polycondensation process, a series of copolyesters composed of pure terephthalate acid (PTA), ethylene glycol (EG), and 1,3‐propanediol (1,3‐PDO) were synthesized. The component, molecular weight, molecular weight distribution, and thermal properties of the copolymers were characterized. The results show that the contents of trimethylene terephthalate (TT) units in the resulting copolyesters are higher than PDO compositions in original diol. Oligomer content in the copolyesters varies with the compositions and attains a minimum value when the TT ingredient is 49.52 mol %. The glass transition temperature (T_g) of the copolyesters varies from 78.5°C for PET (polyethylene terephthalate) to 43.5°C for PTT (polytrimethylene terephthalate) and decreases monotonically with the components. The copolyesters are amorphous copolymers when TT content is in the range of 32.4–40.8 mol %, as calculated from the melting enthalpy (ΔH_m) measured via differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1511–1521 2006     

Crystallization kinetics of poly(trimethylene terephthalate)

The bulk isothermal crystallization kinetics of poly(trimethylene terephthalate) (PTT) was studied using a differential scanning calorimeter. Avrami's theory was used to analyze the data. Based on crystallinity growth rate, Avrami rate constant, K, and crystallization half‐time, PTT's crystallization rate is between those of poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) when compared at the same degree of undercooling. PBT has the highest crystallization rate with K in the order of 10^?2 to 10^?1 min^?n. It is about an order of magnitude faster than PTT at 10^?3 to 10^?2 min^?n, which in turn is an order of magnitude faster than PET with K of 10^?4 to 10^?2 min^?n. Contrary to previous reports (PTT was not included in the study) that aromatic polyesters with odd numbers of methylene units were more difficult to crystallize than the even‐numbered polyesters, PTT did not fit in the prediction and did not follow the odd‐even effect.     

PTT(聚对苯二甲酸丙二醇酯)纤维——一种新型的地毯用纤

本文简要论述了一种新型的适于制作地毯的聚合物——聚对苯二甲酸丙二醇酯(PTT)的合成,纺丝及纤维性能.PTT兼具尼龙高弹性和涤纶易染性,将是一种很有希望的特别适合于纺制地毯的新材料,具有良好的发展前景.     

Applicability of biaxially oriented poly(trimethylene terephthalate) films using bio‐based 1,3‐propanediol in retort pouches

Poly(trimethylene terephthalate) (PTT) is a material that has intermediate properties between poly(ethylene terephthalate) (PET) and nylon, and produced by polymerizing bio‐based 1,3‐propanediol and terephthalic acid. In this study, the possibility of replacing existing biaxially oriented PET (OPET) and nylon 6 (ONylon) film with biaxially oriented PTT (OPTT) film is investigated to develop a more environmentally friendly retort pouch. In order to define actual problems in the retort pouch manufacturing process, food process, and distribution process, extensive examinations are conducted to study the degradation of physical properties after the in‐processing and sterilization process, the testing of pinhole resistance caused by stress, and the box level drop test. The results show OPTT film to be a promising alternative for OPET and ONylon film, to a limited extent. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46251.