@article{wu_li_wu_cuculo_2002, title={Structure and property studies of poly(trimethylene terephthalate) high-speed melt spun fibers}, volume={43}, ISSN={["0032-3861"]}, DOI={10.1016/S0032-3861(02)00306-3}, abstractNote={Poly(trimethylene terephthalate) has been melt spun at various take-up velocities from 0.5 to 8 km/min to prepare fiber samples. The effect of take-up velocity on the structure and properties of as-spun fibers has been characterized through measurements of birefringence, density, wide-angle X-ray scattering, DSC melting behavior, tensile properties and boiling water shrinkage (BWS). The birefringence exhibits a maximum at take-up velocities between 3 and 4 km/min. The fiber samples spun at the lower take-up speeds have essentially amorphous structures, while the filaments prepared at a velocity range higher than 4 km/min all possess an obvious crystalline structure. With increasing take-up speed, a steady improvement in tensile strength, elongation to break, and BWS is found, whereas the initial modulus remains almost constant within the measurement error, over the entire take-up speed range between 0.5 and 8 km/min.}, number={18}, journal={POLYMER}, author={Wu, G and Li, HW and Wu, YQ and Cuculo, JA}, year={2002}, month={Aug}, pages={4915–4922} }
 @article{wu_li_cuculo_2000, title={Fiber structure and properties of poly(ethylene-2,6-naphthalate) obtained by high-speed melt spinning}, volume={41}, ISSN={["0032-3861"]}, DOI={10.1016/S0032-3861(00)00122-1}, abstractNote={High molecular weight poly(ethylene-2,6-naphthalate)(PEN) has been melt spun at various take-up velocities from 0.9 to 10 km/min to prepare fiber samples. The effect of take-up velocity on the structure and properties of as-spun fibers has been characterized through measurements of birefringence, density, wide-angle X-ray diffraction, infrared analysis, DSC melting behavior, tensile properties and high-temperature shrinkage. With increasing take-up speed, a steady trend toward higher as-spun fiber orientation and crystallinity was observed, accompanied by improved physical properties. The WAXD patterns of the as-spun fibers prepared at a velocity range higher than 1.5 km/min indicate that these samples all possess a developed molecular orientation and crystalline structure. At a relatively low take-up velocity that range from 1.5 to 4 km/min, a high level of molecular orientation in both crystalline and amorphous region has been found. This may be attributed to the high spinning stress generated by the high-molecular weight polymer used. In the high take-up speed region of 5–10 km/min, the molecular orientation becomes saturated. The highest tenacity and initial modulus of the as-spun PEN fibers obtained in this region reached ca 8 and 200 g/d, respectively.}, number={22}, journal={POLYMER}, author={Wu, G and Li, QC and Cuculo, JA}, year={2000}, month={Oct}, pages={8139–8150} }
 @article{wu_liu_li_cuculo_2000, title={Structure development and physical properties achieved in the drawing and/or annealing of PEN fibers}, volume={38}, ISSN={["0887-6266"]}, DOI={10.1002/(SICI)1099-0488(20000601)38:11<1424::AID-POLB20>3.0.CO;2-G}, abstractNote={As-spun poly(ethylene-2,6-naphthalate) (PEN) fibers (i.e., precursors) prepared from high molecular weight polymer were drawn and/or annealed under various conditions. Structure and property variations taking place during the treatment process were followed via wide-angle X-ray scattering (WAXS), small-angle X-ray scattering, differential scanning calorimetry (DSC), and mechanical testing. Both the WAXS and DSC measurements of the cold-drawn samples stretched from a low-speed-spun amorphous fiber indicate that strain-induced crystallization can occur at a temperature below the glass-transition temperature and that the resultant crystal is in the α-form modification. In contrast, when the same precursor was subjected to constrained annealing, its amorphous characteristics remained unchanged even though the annealing was performed at 200 °C. These results may imply that the application of stretching stress is more important than elevated temperatures in producing α-form crystallization. The crystalline structure of the hot-drawn samples depends significantly on the morphology of the precursor fibers. When the precursor was wound at a very low speed and in a predominantly amorphous state, hot drawing induced the formation of crystals that were apparently pure α-form modification. For the (3-form crystallized precursors wound at higher speeds, a partial crystalline transition from the β form to the a form was observed during the hot drawing. In contrast with the mechanical properties of the as-spun fibers, those of the hot-drawn products are not improved remarkably because the draw ratio is extremely limited for most as-spun fibers in which an oriented crystalline structure has already formed.}, number={11}, journal={JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS}, author={Wu, G and Liu, M and Li, XN and Cuculo, JA}, year={2000}, month={Jun}, pages={1424–1435} }
 @article{wu_cuculo_1999, title={Structure and property studies of poly(ethylene terephthalate) poly(ethylene-2,6-naphthalate) melt-blended fibres}, volume={40}, ISSN={["0032-3861"]}, DOI={10.1016/S0032-3861(98)00317-6}, abstractNote={The effects of blend composition and take-up velocity on structural variations and physical properties of poly(ethylene terephthalate) [PET]/poly(ethylene-2,6-naphthalate) [PEN] blend fibres were studied using WAXS, n.m.r., d.s.c., density, tensile and thermal shrinkage tests. Over the ranges studied, the structure and properties of the blend fibres were significantly influenced by the composition and melt spinning velocity. With the increase in content of any second component (PEN or PET), the crystallization process in the as-spun fibres becomes difficult, because of the formation of random copolymers via a transesterification reaction occurring between PET and PEN molecules. This reaction also produces a miscible amorphous phase with the result that all blend samples exhibit a single glass transition temperature intermediate to those of the two homopolymers. The WAXS results of annealed samples, however, indicate separate crystals for the two components rather than a co-crystallization. Room temperature mechanical properties, for fibres spun at constant take-up velocity, improved gradually with increasing PEN content. The thermal shrinkage, however, is relatively high for blend fibres and reaches a maximum for the 50/50 PET/PEN blend, indicating that the copolymer chains are oriented fairly well, but exist in the amorphous state.}, number={4}, journal={POLYMER}, author={Wu, G and Cuculo, JA}, year={1999}, month={Feb}, pages={1011–1018} }
 @article{wu_yoshida_cuculo_1998, title={Heat induced shrinkage and microstructural changes in PET: As-spun fibres prepared via 'Controlled Threadline Dynamics'}, volume={39}, ISSN={["0032-3861"]}, DOI={10.1016/S0032-3861(97)10269-5}, abstractNote={Macroscopic shrinkage behaviour and microstructural changes in PET as-spun fibres prepared by a normal cooling and by a `Controlled Threadline Dynamics' (LIB)1 process have been investigated as a function of temperature. For normally cooled spun fibres, the shrinkage and microstructural changes may be respectively divided into two steps with increasing temperature. A significant shrinkage in the low temperature range was attributed mainly to a disorientation process in oriented noncrystalline chains. In the higher temperature region, the still relatively high but gradually decreasing shrinkage is related principally to the diminished disorientation process and a sequential crystallization process. In comparison with the normally cooled spun fibres, a small but monotonically increasing shrinkage was found in the case of the (LIB) samples. Structurally, a monotonic increase in crystallinity and a decrease in fraction of oriented noncrystalline phase were found to accompany the shrinkage behaviour. This indicates that the microstructural change and corresponding shrinkage in the LIB spun fibres is a one-step process. The ultra-high oriented noncrystalline structure which results from the LIB process may promote minimization of distance between molecular chains in the oriented noncrystalline regime, and enhance intermolecular cohesive forces. When the fibres are heat treated, large-scale molecular motion may be restricted because of high intermolecular interaction. Instead, local thermal motion of highly stretched noncrystalline chains may be activated, and the conversion from very taut noncrystalline chains to a crystalline phase may be easier because of smaller intermolecular distances and enhanced cohesive forces. Therefore, the entire process may be characterized mainly as a continuous mass transfer from oriented noncrystalline phase to crystalline phase in situ, eschewing massive molecular recoiling. This may result in restricted disorientation in the noncrystalline phase and consequently accompanied by apparently restricted shrinkage. © Elsevier Science Ltd.}, number={25}, journal={POLYMER}, author={Wu, G and Yoshida, T and Cuculo, JA}, year={1998}, month={Dec}, pages={6473–6482} }
 @misc{cuculo_tucker_lundberg_chen_wu_chen_1998, title={Ultra-oriented crystalline filaments and method of making same}, volume={5,733,653}, number={1998 Mar. 31}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Cuculo, J. A. and Tucker, P. A. and Lundberg, F. and Chen, J.-Y. and Wu, G. and Chen, G.-Y.}, year={1998} }