Fiber and film developments from immiscible blends of cellulose acetate propionate and poly(butylene terephthalate)

Binary blends of cellulose acetate propionate (CAP) and poly(butylene terephthalate) (PBT) in the composition range of 5–15 wt % for CAP were prepared in the form of films and fibers by compression molding and spinning, respectively. The presence of two invariant glass‐transition temperatures corresponding to the CAP and PBT components and viscosities lower than those of the neat PBT of the CAP–PBT blends implied that the CAP–PBT blends were immiscible. Moreover, the crystallinity of the PBT component was higher in the spun fibers than in the films; this was possibly due to the different cooling methods or the chain orientation in the spinning process. In the meantime, the CAP component could not undergo crystallization because of its rigid structure and alkyl substituents. For the CAP–PBT films, the amorphous CAP was present as dispersed particles in the PBT matrix; but it became rods in the spun fibers. In addition, the presence of the amorphous CAP resulted in a decrease in the tensile strength and an increase in the elongation at break for the CAP–PBT fibers. The CAP–PBT films and fibers could be applied in a wide range of applications requiring renewable properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45013.     

Poly(butylene terephthalate)/poly(ethylene glycol) blends with compatibilizers

Polymer blend systems offer a versatile approach for tailoring the properties of polymer materials for specific applications. In this study, we investigated the compatibility of polybutylene terephthalate (PBT) and poly(ethylene glycol) (PEG) blends processed using a twin-screw extruder, with the aim of enhancing their compatibility. Phthalic anhydride (PAn) and phthalic acid (PAc) were used as potential compatibilizers at different concentrations to improve interfacial interactions between PBT and PEG. Blend morphologies were characterized using scanning electron microscopy, which revealed improved interfacial compatibility and reduced phase separation with the incorporation of small amounts of PAn and PAc. Differential scanning calorimetry analysis indicated changes in the melting temperature (T_m) and glass transition temperature (T_g) of the blends owing to the compatibilizing effects of PAn and PAc. Dynamic mechanical analysis further corroborated the influence of the compatibilizers on the T_g and viscoelastic behavior. Thermogravimetric analysis demonstrated enhanced thermal stability with the addition of either PAn or PAc. Rheological measurements indicated an increase in complex viscosity with increasing compatibilizer content, indicating improved compatibility. The degradation point (T_d) of PBT/PEG blend increased from 158 to 200 and 319°C with the incorporation of 5 phr PAn and 2 phr PAc, respectively. Mechanical properties, including tensile strength, Young's modulus, and Izod impact strength, were evaluated. For instance, the tensile strength of PBT/PEG blend was enhanced from 43.5 to 48.7 and 49.7 MPa by incorporating 5 phr PAn and 2 phr PAc, respectively. However, the impact strength of PBT/PEG blend increased from 3.0 to 4.3 and 4.2 kJ/m² with the addition of 1 phr PAn and 1 phr PAc, respectively. The findings demonstrated that adding 5 phr PAn or 2 phr PAc to the PBT/PEG blends was advantageous, achieving a harmony of performance benefits and compromises. Rheological observations contributed significantly to the mechanical and thermal properties. Overall, the study highlights the significance of utilizing PAn and PAc as effective compatibilizers for enhancing the properties of PBT/PEG blends, making them potential candidates for various applications.     

强韧化PBT/PC共混物的制备与性能

采用自制的甲基丙烯酸缩水甘油酯熔融接枝丙烯腈丁二烯苯乙烯三元聚合物\[ABS-g-(GMA-co-St),AGS]为改性剂,对聚对苯二甲酸丁二醇酯（PBT）/聚碳酸酯(PC)（80/20）共混物进行改性研究。通过扫描电子显微镜、差示扫描量热仪、力学性能和流变性能测试研究了改性后共混物的性能。结果表明,随着AGS含量的增加,共混物中两相间的界面黏结增强; AGS对PBT/PC共混物具有强韧化的作用,与未添加AGS的PBT/PC共混物相比,当AGS含量为10份时,共混物的缺口冲击强度和拉伸强度分别提高了49.8 %和17.4 %;AGS的加入提高了共混物的界面强度和相容性;添加AGS能够提高共混物的结晶峰温度,起到促进晶粒生长的作用。     

Thermal and mechanical properties of poly(butylene terephthalate)/epoxy blends

In this study, melt blends of poly(butylene terephthalate) (PBT) with epoxy resin were characterized by dynamic mechanical analysis, differential scanning calorimetry, tensile testing, Fourier transform infrared spectroscopy, and wide‐angle X‐ray diffraction. The results indicate that the presence of epoxy resin influenced either the mechanical properties of the PBT/epoxy blends or the crystallization of PBT. The epoxy resin was completely miscible with the PBT matrix. This was beneficial to the improvement of the impact performance of the PBT/epoxy blends. The modification of the PBT/epoxy blends were achieved at epoxy resin contents from 1 to 7%. The maximum increase of the notched Izod impact strength (≈ 20%) of the PBT/epoxy blends was obtained at 1 wt % epoxy resin content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Critical inter-particle distance dependence and super-toughness in poly(butylene terephthalate)/grafted poly(ethylene-octene) copolymer blends by means of polyarylate addition

New super-tough poly(butylene terephthalate) (PBT) materials were obtained modifying with 10 wt% polyarylate (PAr) a PBT/maleic anhydride grafted poly(ethylene-octene) copolymer (mPEO) blend with mPEO contents from 0 to 30 wt%. PAr was fully miscible in the PBT phase. The presence of mPEO did not influence either the nature or the crystallinity of the PBT-PAr matrix. The decrease in interfacial tension and particle size upon grafting of PEO, indicated that compatibilization took place. The maximum toughness obtained was very high (impact strength more than twenty-fold that of the PBT-PAr matrix). Moreover, it was attained with only 7.5% PEO maleinized at 0.63%, and was accomplished by an increase in stiffness of the blends. The successful modification of the matrix consolidates this method as a new one to improve impact toughness. The critical inter-particle distance (τ_c) appears as the parameter that control super-toughness in these blends, and it is proposed to depend on adhesion measured by means of the interfacial tension.     

Two-stage crystallization kinetics modeling of a miscible blend system containing crystallizable poly(butylene terephthalate)

A modified two-stage kinetic model is proposed to describe the crystallization/solidification from the melt state of a miscible binary blend system comprising amorphous poly(ether imide) (PEI) and crystallizable poly(butylene terephthalate) (PBT). Differential scanning calorimetry (DSC) was employed to monitor the isothermal melt-crystallization of the PBT/PEI blends. A nonlinear regression method was adopted for estimating the kinetic parameters in accordance with the modified two-stage series-parallel model in comparison with the Avrami model. The results suggested that the crystallization of the PEI/PBT blends could be more precisely described by using the modified model, which properly takes into account the changing mechanisms from early to later stage of crystallization. For practical applications, an optimal temperature window for solidifying PEI/PBT miscible blends may be determined by utilizing this model.     

Properties of poly(butylene terephthalate)/functionalized polyolefin blends

The object of this study was to investigate the physical properties and morphology of melt-mixed blends containing poly(butylene terephthalate) (PBT) with several functionalized polyolefins such as ethylene/vinyl acetate copolymer (EVA), EVA-g-maleic anhydride (EVA-g-MAH), EVA-g-ACID, EVA-g-ACID/ACRYLATE, ethylene methacrylate-g-MAH (EMA-g-MAH), ethylene/ethyl acrylate copolymer (EEA) and an ethylene ionomer. Special focus was made on PBT/EVA-g-MAH and PBT/EMA-g-MAH blends compared with PBT/EVA and PBT/EMA blends. Blends were prepared in a counter-rotating twin-screw extruder. Mechanical and thermal properties, glass transition temperature and morphology were examined using a tensile testing machine, differential scanning calorimeter (DSC), dynamic mechanical analysis and Scanning Electron Microscope (SEM). PBT/EVA-g-MAH and PBT/EMA-g-MAH blends exhibited better impact strength than PBT/EVA and PBT/EMA blends because of the larger interfacial adhesion of EVA-g-MAH and EMA-g-MAH with PBT than EVA and EMA.     

Molecular orientation and mechanical properties of polymer blends of PBT and a liquid crystalline polyester

A thermotropic liquid crystalline polyester (LCP) based on 4-hydroxyacetophenone azine and sebacoyl dichloride was synthesized via a low-temperature solution route. The liquid crystalline polymer was characterized by ¹H-NMR, DSC, GPC, and polarizing microscopy experiments. The LCP was melt-blended with poly(butylene terephthalate) (PBT), followed by the melt-spinning process at take-up speeds ranging from 14 to 50 m/min. We analyzed the molecular orientational order of LCP and PBT in as-spun fibers of the LCP/PBT blends by the attenuated total reflection (ATR) FTIR dichroism technique and WAXS. The order parameter (S), representing the molecular orientational order, of LCP in the polyblend fibers increased as the employed LCP amounts and the draw ratio increased. Moreover, the order parameter of PBT in the blends increased dramatically when sufficiently large amounts of LCP (over 50 wt %) were employed, especially for highly drawn fibers, which suggested a considerable miscibility between LCP and PBT. The thermal behavior of the blends investigated by DSC also indicated that the synthesized LCP was miscible, at least partially, with PBT. All these results correlated with the enhancement of mechanical properties observed for higher concentrations of LCP in the blends and for highly drawn samples. © 1996 John Wiley & Sons, Inc.     

Phase behavior of blends containing amorphous poly(resorcinol phthalate‐block‐carbonate) and semicrystalline polyesters

The phase behavior of poly(resorcinol phthalate‐block‐carbonate) (RPC) with engineering polyesters was investigated by using differential scanning calorimeter (DSC) and dynamic mechanical analysis. RPC was found to form miscible blends with poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), and poly(cyclohexylmethylene terephthalate) (PCT), but was partially miscible with poly(1,4‐cyclohexanedimethylene‐1,4‐cyclohexanedicarboxylate) (PCCD) in the melt state and below the melting temperature (T_m). The degree of melting‐point depression indicates that the RPC is most miscible with PCT followed by PET and then PBT. Furthermore, with the help of empirical DSC data and the Nishi–Wang equation, the interaction parameters between RPC and PET, PBT, and PCT were quantified to be ?0.36, ?0.33, and ?0.54, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Biodegradable polymer blends of poly(lactic acid) and poly(ethylene glycol)

Poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) were melt-blended and extruded into films in the PLA/PEG ratios of 100/0, 90/10, 70/30, 50/50, and 30/70. It was concluded from the differential scanning calorimetry and dynamic mechanical analysis results that PLA/PEG blends range from miscible to partially miscible, depending on the concentration. Below 50% PEG content the PEG plasticized the PLA, yielding higher elongations and lower modulus values. Above 50% PEG content the blend morphology was driven by the increasing crystallinity of PEG, resulting in an increase in modulus and a corresponding decrease in elongation at break. The tensile strength was found to decrease in a linear fashion with increasing PEG content. Results obtained from enzymatic degradation show that the weight loss for all of the blends was significantly greater than that for the pure PLA. When the PEG content was 30% or lower, weight loss was found to be primarily due to enzymatic degradation of the PLA. Above 30% PEG content, the weight loss was found to be mainly due to the dissolution of PEG. During hydrolytic degradation, for PLA/PEG blends up to 30% PEG, weight loss occurs as a combination of degradation of PLA and dissolution of PEG. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1495–1505, 1997     

Stiffer and super-tough poly(butylene terephthalate) based blends by modification with phenoxy and maleated poly(ethylene-octene) copolymers

New super-tough poly(butylene terephthalate) (PBT) materials were obtained by melt blending PBT with both 20 wt% phenoxy (Ph) and 0-30 wt% maleic anhydride grafted poly(ethylene-octene) (mPEO) copolymers with different grafting levels. Ph was completely miscible in the PBT matrix. The presence of mPEO did not influence either the nature of the PBT-Ph matrix or the crystallization of PBT. The overall decrease in particle size and in interfacial tension upon grafting indicated that compatibilization had taken place. Super-tough (impact strength 23-fold that of the PBT) and stiffer PBT based blends were obtained at mPEO contents equal to or higher than 15%. The dependence of the critical inter-particle distance (τ_c), on both adhesion measured by means of the interfacial tension, and on the relation between the modulus of the matrix and that of the rubbery dispersed phase (E_m/E_d), is proposed.     

Poly(butylene terephthalate)/poly(ε‐caprolactone) blends: Miscibility and thermal and mechanical properties

Miscibility and thermal and mechanical properties of poly(butylene terephthalate) (PBT) blends with poly(ε‐caprolactone) (PCL) were analyzed as a function of the molecular mass of PCL. It was found that the components are miscible when oligomeric PCL is blended with PBT, probably due to favorable interactions between ? OH end groups of poly(ε‐caprolactone) and ester groups of PBT. In the blends containing high molar mass PCL, the concentration of hydroxyl end groups is lower, allowing only partial miscibility of the components. The resulting materials display good mechanical properties, with enhanced performance at rupture compared to plain PBT. POLYM. ENG. SCI., 47:323–329, 2007. © 2007 Society of Plastics Engineers.     

The incorporation and release of ungeremine,an antifungal Amaryllidaceae alkaloid,in poly(lactic acid)/poly(ethylene glycol) nanofibers

Ungeremine (UNG) is an alkaloid typically isolated from Pancratium maritimum or synthesized by the oxidation of lycorine. This antifungal alkaloid was incorporated into electrospun nanofibers based on blends of poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG). The effect of the UNG on the structure, morphology, and thermal properties of the fibers was evaluated, and the release of the alkaloid from the fibers was quantified. Studies on the release of the UNG for the nanofibers show that the release rate is related to the amount and distribution of the PEG in the nanofiber matrix. Initial burst release of the antifungal alkaloid is related to the PEG in the nanofibers, where after a sustained release occurs indicating that the UNG is present in both the PLA and PEG domains in the nanofibers.     

PTT/PBT共混体系及可纺性探究

研究了PTT/PBT共混体系的相容性和结晶性能,并对体系的可纺性作了初步探究。结果表明:PTT/PBT共混体系在无定形区具有较好的相容性,但在晶区是晶相分离的。在冷结晶过程中,当PBT含量超过20%时,将促进体系的结晶性能;而在熔融结晶过程中,第二组分的加入抑制了体系的结晶性能,当配比为50/50时,结晶速率相对最低。另外,PTT/PBT共混体系表现出了良好的可纺性,共混纤维的断裂伸长率随着拉伸倍数和体系中PBT含量的增大而减小,强度增大,但稍差于纯组分纤维;当PTT含量达到50%后,共混纤维表现出了明显优于纯PBT纤维的回弹性,而当PTT含量达到70%时,共混纤维的回弹性能已接近纯PTT纤维。     

Rheological behavior of polyester blend and mechanical properties of the polypropylene–polyester blend fibers

The article deals with method of preparation, rheological properties, phase structure, and morphology of binary blend of poly(ethylene terephthalate) (PET)/poly(butylene terephthalate) (PBT) and ternary blends of polypropylene (PP)/(PET/PBT). The ternary blend of PET/PBT (PES) containing 30 wt % of PP is used as a final polymer additive (FPA) for blending with PP and subsequent spinning. In addition commercial montane (polyester) wax Licowax E (LiE) was used as a compatibilizer for spinning process enhancement. The PP/PES blend fibers containing 8 wt % of polyester as dispersed phase were prepared in a two‐step procedure: preparation of FPA using laboratory twin‐screw extruder and spinning of the PP/PES blend fibers after blending PP and FPA, using a laboratory spinning equipment. DSC analysis was used for investigation of the phase structure of the PES components and selected blends. Finally, the mechanical properties of the blend fibers were analyzed. It has been found that viscosity of the PET/PBT blends is strongly influenced by the presence of the major component. In addition, the major component suppresses crystallinity of the minor component phase up to a concentration of 30 wt %. PBT as major component in dispersed PES phase increases viscosity of the PET/PBT blend melts and increases the tensile strength of the PP/PES blend fibers. The impact of the compatibilizer on the uniformity of phase dispersion of PP/PES blend fibers was demonstrated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4222–4227, 2006     

环氧化三元乙丙橡胶对PBT结构及性能的影响

将三元乙丙橡胶（EPDM）经环氧化反应制得的环氧化三元乙丙橡胶（eEPDM）与聚对苯二甲酸丁二醇酯（PBT）熔融共混以改善PBT的缺口冲击韧性。利用红外光谱、核磁共振谱仪、动态机械热分析仪、差示扫描量热仪、扫描电子显微镜、转矩流变仪及拉伸仪与缺口冲击仪对eEPDM的结构及PBT/eEPDM的相容性、相结构、流变性能及力学性能进行了表征。结果表明,EPDM成功引入了环氧基团;PBT与eEPDM部分相容;橡胶含量低于15 %时,分散相粒径较小且分散均匀;橡胶相含量高于15 %时,分散相粒径变大且分散不均匀;添加eEPDM使得PBT的扭矩变大;eEPDM含量为5 %时,共混物的缺口冲击韧性可提高1倍。     

The effect of tension during drying on the structure and mechanics of poly(p-phenylene benzobisthiazole) fibers

The effect of tension during drying on the structure and mechanics of poly(p-phenylene benzobisthiazole) (PBT) fibers has been investigated. The application of tension during drying on PBT fibers spun from anisotropic solutions of PBT/Polyphosphoric acid (PPA) results in an enhancement of tensile modulus and yield strength with a reduction in strain to break. The alterations in the tensile properties can be attributed to the straightening of the wet fibrillar network and the reduction in the axial compressive stresses which develop during drying. Modifications in the mechanical behavior of PBT fibers through tension drying can be achieved regardless of the initial spin draw ratio of the fiber. Additionally, tension drying provides a means to maximize the potential stiffness of PBT fibers which have a low spin draw ratio. Lastly, these investigations show that in the processing of PBT fibers, preventing the onset of buckling and aligning the wet fibrillar network with tension during drying is more effective in enhancing the tensile properties than straightening the dried buckled fibers.     

Influence of high density polyethylene‐g‐maleic anhydride on compatibility and properties of poly(butylene terephthalate)/high density polyethylene blends

Poly(butylene terephthalate)/high density polyethylene (PBT/HDPE) blends and PBT/HDPE‐grafted maleic anhydride (PBT/HDPE‐g‐MAH) blends were prepared by the reactive extrusion approach, and the effect of blend compositions on the morphologies and properties of PBT/HDPE blends and PBT/HDPE‐g‐MAH blends was studied in detail. The results showed that flexural strength, tensile strength, and notched impact strength of PBT/HDPE blends decreased with the addition of HDPE, and flexural strength and tensile strength of PBT/HDPE‐g‐MAH blends decreased, while the notched impact strength of PBT/HDPE‐g‐MAH increased with the addition of HDPE‐g‐MAH. Compared with PBT/HDPE blends, the dimension of the dispersed phase particles in PBT/HDPE‐g‐MAH blends was decreased and the interfacial adhesion was increased. On the other hand, the effects of HDPE and HDPE‐g‐MAH contents on the crystalline and the rheological properties of the blends were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6081–6087, 2006     

Effect of Blend Ratio and Draw Ratio on the Mechanical Properties of PET/PP Blended Conjugate Fibers

This study analyzes the influence of blend ratio and draw ratio on the fiber properties of blend fibers composed of poly (ethylene terephthalate), or PET, and polypropylene, or PP, (hereafter referred to as PET/PP conjugate fibers). For a comparison, PET and poly (butylene terephthalate), or PBT blends, (hereafter referred to as PET/PBT conjugate fibers) are also investigated. Various blend ratios of fibers are melt spun and drawn in a multistep drawing method. The conjugate fibers are evaluated using tenacity, Young's modulus, wide-angle X-ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) tests. The results show that multistep drawing using a lower first-step draw ratio provides a higher tenacity and Young's modulus. Furthermore, when the blend ratio is 75/25 in a PET/PP conjugate fiber and 50/50 in a PET/PBT conjugate fiber, the polymer components undergo a phase inversion phenomenon. A PP sub-micron (10^?1 ～ 10⁰ micron) fiber of about 0.0001 ～ 0.00017 tex in fineness, or about 0.4 ～ 0.5 micron in diameter, can be obtained when PET/PP conjugate fiber is treated with a 25% NaOH aqueous solution by weight. However, A PBT sub-micron fiber cannot be achieved using a PET/PBT conjugate fiber.     

Formation and morphology development of poly(butylene terephthalate) nanofibers from poly(butylene terephthalate)/cellulose acetate butyrate immiscible blends

Nano‐scale poly(butylene terephthalate) (PBT) fibers were prepared from PBT/cellulose acetate butyrate (CAB) immiscible polymer blends due to in situ microfibrillar formation during a melt extruding process. The morphological development of the dispersed phase was studied with samples collected at different zones in a twin screw extruder. It was found that the holistic developmental trends of PBT dispersed phase were nearly the same. Fibers began to form even under the shear flow of the twin‐screw extruder. The morphology developmental mechanism of the dispersed phase involved the formation of sheets, holes and network structures, then the size reduction and formation of nanofibers. The effect of viscosity ratio, blend ratio, and shear rate on the morphology evolution was also studied by analyzing the shape and size distribution of the samples. The diameter distribution of the nanofibers could be affected by viscosity ratio, blend ratio, and shear rate. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers