回用聚酯的熔融共混改性研究进展

综述了国内外回用聚对苯二甲酸乙二酯(R-PET)熔融共混改性的研究进展。异氰酸酯及均苯四酸二酐等扩链剂共混改性R-PET,通过共混熔融挤出,可提高R-PET的相对分子质量;有机聚合物如常规PET、聚烯烃(聚乙烯、聚丙烯以及接枝共聚物)、聚碳酸酯及聚碳酸酯的多组分混合物等共混改性R-PET,可提高共混材料力学性能;玻璃纤维、岩石纤维以及纳米有机粘土共混改性R-PET,可获取增强复合材料。     

涤棉织物化学回收工艺研究

以废旧涤棉织物为原料,乙二醇(EG)为醇解剂,通过改变醇解时间、醇解温度、EG/废旧涤棉织物中聚对苯二甲酸乙二醇酯(PET)质量比(mEG/mPET)、催化剂种类及用量等研究了蓬松态下废旧涤棉织物的醇解工艺,以及醇解过程对涤棉织物中棉纤维性能的影响。结果表明:随着醇解时间、醇解温度的提高,mEG/mPET的增大,涤棉织物的醇解程度增大,各参数达到一定程度后醇解程度基本不变;最佳醇解工艺为涤棉织物中mEG/mPET为2/1,催化剂用量为涤棉织物中PET质量的0.30%,醇解温度196℃,醇解时间1 h;在乙酸锌、碳酸钠、乙酸钾、氯化镁4种催化剂中,碳酸钠综合催化效果最佳;经醇解过程后涤棉织物中棉纤维表面变得粗糙,力学性能有较大下降。     

Essential Work of Fracture Parameters of in‐situ Microfibrillar Poly(ethylene terephthalate)/Polyethylene Blend: Influences of Blend Composition

Summary: An in‐situ microfibrillar blend based on poly(ethylene terephthalate) (PET) and polyethylene (PE) was fabricated through slit die extrusion, hot‐stretching and quenching. The morphology of the PET in‐situ microfibers, which were observed after the matrix was etched away, appears to be dependent on the blend composition at a fixed hot stretch ratio. The well‐defined in‐situ fibers were generated at the PET concentrations ranging from 15 to 25 wt.‐%. The fracture toughness of the microfibrillar blend was evaluated using deeply double‐edge notched tension (DDENT) specimens according to the essential work of fracture procedure. Initially, the increase of PET concentration makes w_e rise. At 15 wt.‐% of PET concentration there exists a maximum w_e. Further increase of PET microfibers causes a rapid decrease of w_e. On the other hand, incorporation of PET microfibers at a low concentration to PE makes w_p rise slightly. As it exceeds 10 wt.‐%, w_p decreases substantially. It was believed that the characteristics of the PET microfibers were responsible for the fracture behaviors of the microfibrillar blend.

Morphology of PET microfibers in the PET/PE microfibrillar blend in which the matrix PE was etched away by hot xylene.     

Kinetics and thermal crystallinity of recycled PET. I. Dynamic cooling crystallization studies on blends recycled with engineering PET

The recycled poly(ethylene terephthalate) (R-PET) from the recovery of a blow-molded bottle is studied with its crystalline behavior in terms of glass transition temperature (T_g), crystallization temperature (T_c), melting temperature (T_m), and its dynamic crystallization kinetics. These crystalline behaviors offer an explanation of the better mechanical properties of the R-PET. Thermal cycles of the processes of the R-PET and its blending specimens with engineering PET (E-PET) show the importance of the thermal treatment of the plastic PET in the improvements of mechanical strength and increased crystallinity. Tenfold and fivefold increases, respectively, of elongation and impact strength are observed in the specimen of R-/E-PET of 20/80 weight ratio blend, better than that of E-PET alone. A nearly 20-fold increase of the crystallization rate constant (K) at 190°C for the same R-/E-20/80 blend is observed. The Avrami exponent (“n”) is found to be variable with temperature. The changing crystallization mechanisms are mainly the result of the competition between the nucleating and growing of crystallites in response to the temperature-controlling factor at the melt state. © 1996 John Wiley & Sons, Inc.     

Flame retardant finishing of the polyester/cotton blend fabric using a cross‐linkable hydroxy‐functional organophosphorus oligomer

Blend fabrics of cotton and polyester are widely used in apparel, but high flammability becomes a major obstacle for applications of those fabrics in fire protective clothing. The objective of this research was to investigate the flame retardant finishing of a 50/50 polyester/cotton blend fabric. It was discovered previously that N,N′‐dimethyloldihydroxyethyleneurea (DMDHEU) was able to bond a hydroxy‐functional organophosphorus oligomer (HFPO) onto 50/50 nylon/cotton blend fabrics. In this research, the HFPO/DMDHEU system was applied to a 50/50 polyester/cotton twill fabric. The polyester/cotton fabric treated with 36% HFPO and 10% DMDHEU achieved char length of 165 mm after 20 laundering cycles. The laundering durability of the treated fabric was attributed to the formation of polymeric cross‐linked networks. The HFPO/DMDHEU system significantly reduced peak heat release rate (PHRR) of cotton on the treated polyester/cotton blend fabric, but its effects on polyester were marginal. HFPO/DMDHEU reduced PHRR of both nylon and cotton on the treated nylon/cotton fabric. It was also discovered that the nitrogen of DMDHEU was synergistic to enhance the flame retardant performance of HFPO on the polyester/cotton fabric.     

TRANSCRYSTALLIZATION WITH REORIENTATION OF POLYETHYLENE IN A DRAWN PET/PE BLEND AS REVEALED BY WAXS OF SYNCHROTRON RADIATION

A cold drawn blend of poly(ethylene terephthalate) (PET) and polyethylene (PE) (50/50 by wt.) was investigated during heating, melting, and subsequent crystallization upon cooling of PE by means of wide-angle X-ray scattering (WAXS) of synchrotron radiation. Strong epitaxial effects of the highly oriented PET on the very first stages of non-isothermal crystallization of PE during cooling of the cold drawn blend from 160°C to room temperature were found. WAXS shows that transcrystalline PE layers are formed around the PET fibrils. Within these layers, the PE crystallites are partly oriented at 90° with respect to their initial orientation (draw direction).     

PET/EHDPET共混纤维的碱水解行为

将PET和易水解聚酯（EHDPET）以适当比例混合，可制得以EHDPET为分散相的共混纤维。将该纤维进行碱水处理，可得到纤维表面具有凹坑、内部均匀分布微孔的异状纤维。     

Microstructure and crystallization of melt‐mixed poly(ethylene terephthalate)/poly(ethylene isophthalate) blends

Physical blends of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI), abbreviated PET/PEI (80/20) blends, and of PET and a random poly(ethylene terephthalate‐co‐isophthalate) copolymer containing 40% ethylene isophthalate (PET₆₀I₄₀), abbreviated PET/PET₆₀I₄₀ (50/50) blends, were melt‐mixed at 270°C for different reactive blending times to give a series of copolymers containing 20 mol % of ethylene isophthalic units with different degrees of randomness. ¹³C‐NMR spectroscopy precisely determined the microstructure of the blends. The thermal and mechanical properties of the blends were evaluated by DSC and tensile assays, and the obtained results were compared with those obtained for PET and a statistically random PETI copolymer with the same composition. The microstructure of the blends gradually changed from a physical blend into a block copolymer, and finally into a random copolymer with the advance of transreaction time. The melting temperature and enthalpy of the blends decreased with the progress of melt‐mixing. Isothermal crystallization studies carried out on molten samples revealed the same trend for the crystallization rate. The effect of reaction time on crystallizability was more pronounced in the case of the PET/PET₆₀I₄₀ (50/50) blends. The Young's modulus of the melt‐mixed blends was comparable to that of PET, whereas the maximum tensile stress decreased with respect to that of PET. All blend samples showed a noticeable brittleness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3076–3086, 2003     

Shear rate dependence of viscosity and first normal stress difference of LCP/PET blends at solid and molten states of LCP

The liquid crystalline polymer (LCP) and polyethylene terephthalate (PET) were blended in an elastic melt extruder to make samples having 20, 40, 60, 80, and 100 wt % of LCP. Morphology of these samples was studied using scanning electron microscopy. The steady state shear viscosity (η), dynamic complex viscosity (η*) and first normal stress difference (N₁) were evaluated and compared at two temperatures: 265°C, at which LCP was in solid state, and 285°C, at which LCP was in molten state. The PET was in molten state at both the temperatures. The shear viscosity of the studied blends displayed its dependence on composition and shear rate. A maxima was observed in viscosity versus composition plot corresponding to 80/20 LCP/PET blend. The N₁ increased with LCP loading in PET and with the increased asymmetry of LCP droplets. The N₁ also varied with the shear stress in two stages; the first stage demonstrated elastic deformation, whereas second stage displayed dominant plastic deformation of LCP droplets. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2212–2218, 2007     

Chemical grafting of curcumin at polyethylene terephthalate woven fabric surface using a prior surface activation with ultraviolet excimer lamp

Durable curcumin‐treated antibacterial polyethylene terephthalate (PET) fabrics (against Staphylococcus aureus) were produced by dyeing with curcumin after surface activation using vacuum ultraviolet excimer lamp at 172 nm. Surface change properties of the exposed fabrics were characterized by surface analysis methods such as wettability, atomic force microscopy, and X‐ray photoelectron spectroscopy. Results show an increase in surface hydrophilicity with a water contact angle of the PET fabric reaching 24° after 10 min excimer irradiation, which could be attributed to an increase in carboxyl group formation as confirmed by X‐ray photoelectron spectroscopy measurements. Varying concentrations of curcumin were immobilized onto untreated and vacuum ultraviolet‐irradiated PET samples using diffusion method at 90°C, and the treated fabrics characterized using K/S (color strength) values at 440 nm. K/S values increased when the PET surface was subjected to a prior excimer irradiation, because of grafting of curcumin at the PET surface. Increased excimer irradiation time increased grafting of curcumin because the inner fabric fiber surfaces were also more thoroughly treated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improved compatibility of high‐density polyethylene/poly(ethylene terephthalate) blend by the use of blocked isocyanate group

The blocked isocyanate group (BHI) was synthesized to improve the storage stability of HI (2‐hydroxyethyl methacrylate combined with isophorone diisocyanate) and characterized by Fourier transform infrared spectroscopy (FTIR). High‐density polyethylene grafted with the blocked isocyanate group (HDPE‐g‐BHI) was used as a reactive compatibilizer for an immiscible high‐density polyethylene/poly(ethylene terephthalate) (HDPE/PET) blend. A possible reactive compatibilization mechanism is that regenerated isocyanate groups of HDPE functionalized by BHI react with the hydroxyl and carboxyl groups of PET during melt blending. The HDPE‐g‐BHI/PET blend showed the smaller size of a dispersed phase compared to the HDPE/PET blend, indicating improved compatibility between HDPE and PET. This increased compatibility was due to the formation of an in situ graft copolymer, which was confirmed by dynamic mechanical analysis. Differential scanning calorimetry (DSC) analysis represented that there were few changes in the crystallinity for the continuous PET phase of the HDPE‐g‐BHI/PET blends, compared with those of the HDPE/PET blends at the same composition. Tensile strengths and elongations at the break of the HDPE‐g‐BHI/PET blends were greater than those of the HDPE/PET blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1017–1024, 2000     

PET/PHA共混纺丝研究

通过差示扫描量热(DSC)分析、X射线衍射和应力-应变分析对聚对苯二甲酸乙二醇酯(PET)与聚羟基脂肪酸酯(PHA)共混纤维的结晶、取向及力学性能进行测试,考察了共混体系的可纺性.结果表明:随着PHA添加量的增大,共混体系的可纺性下降.添加PHA质量分数小于2.5%时,可纺性良好,添加PHA质量分数小于1.5%时,PH...     

Crystallization kinetics of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) blends

The crystallization kinetics of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) (PET/PEN) blends were investigated by DSC as functions of crystallization temperature, blend composition, and PET and PEN source. Isothermal crystallization kinetics were evaluated in terms of the Avrami equation. The Avrami exponent (n) is different for PET, PEN, and the blends, indicating different crystallization mechanisms occurring in blends than those in pure PET and PEN. Activation energies of crystallization were calculated from the rate constants, using an Arrhenius‐type expression. Regime theory was used to elucidate the crystallization course of PET/PEN blends as well as that of unblended PET and PEN. The transition from regime II to regime III was clearly observed for each blend sample as the crystallization temperature was decreased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 23–37, 2001     

纤维用PET/CGP的共混改性研究

采用聚对苯二甲酸乙二醇酯(PET)与聚对苯二甲酸乙二醇酯聚对苯二甲酸丁二醇酯聚丁二醇共聚酯(CGP)以不同比例共混制得一系列的改性聚酯,研究了共混改性聚酯切片的热性能和流变性能。结果表明,随着CGP加入量的增加,PET/CGP共混体系的玻璃化转变温度Tg,冷结晶峰温度Tc和熔点Tm均有所下降,热稳定性比普通PET低;PET/CGP熔体呈现“切力变稀”现象,其表观黏度明显下降。     

Improved antimicrobial activity of polypropylene and cotton nonwoven fabrics by surface treatment and modification with chitosan

Nonwoven polypropylene and cotton fabrics were subjected to plasma pretreatment followed by flash evaporation and radiation crosslinking acrylate polymer coating, which is based on a vacuum deposition, solvent free, process that produces high quality, uniform fabrics with various thicknesses (0.05–5.0 μm). These treated fabrics were then dipped into chitosan, carboxymethyl chitosan, and carboxymethyl chitin solution. These polysaccharides form strong complexes with the modified surface. The antimicrobial activity of these treated samples was then evaluated for their antifungal and antibacterial properties. The antifungal activity for Fusarium oxysporum f. sp. lycopersici, Verticillium albo‐atrum, and Alternaria solani (A. alternata) were examined by the disc plate method. The antibacterial activities of the modified fabrics against Clavibacter michiganensis and Pseudomonas solanacearum were also examined by the viable cell counting method. The inhibition zone of the chitosan covered samples has increased by a factor of 2–3.1 over the original pretreated samples. The chitosan‐modified fabrics showed a good antibacterial activity in killing almost 10⁵ cells/mL within 18–23 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

PET/PP blending by using PP‐g‐MA synthesized by solid phase

In attempts to improve the compatibility of polypropylene (PP) with polyethylene terephthalate (PET), a maleic anhydride grafted PP (PP‐g‐MA) was evaluated as a compatibilizer in a blend of 30/70 wt % PP/PET. PP‐g‐MA was produced from isotactic homopolymer PP utilizing the technique of solid phase graft copolymerization. Qualitative confirmations of the grafting were made by Fourier transform infrared spectroscopy (FTIR). Three different weight percent of compatibilizer, PP‐g‐MA, i.e., 5, 10, and 15 wt % have been used in PP/PET blends. The compatibilizing efficiency for PP/PET blend was examined using differential scanning calorimetry (DSC), optical microscopy (OM), scanning electron microscopy (SEM) of crycrofractured surfaces, and energy dispersive X‐ray spectrum (EDAX). The results show that the grafted PP promotes a fine dispersed phase morphology, improves processability, and modifies the crystallization behavior of the polyester component. These effects are attributed to enhance phase interaction resulting in reduced interfacial tension. Also, the results show that the compatibilizing effects of the three amounts of grafted PP in blend are different and dependent on the amount used. Adding 10 wt % of compatibilizer into blend produced the finest dispersed morphology. Elemental analysis results show that PP is matrix. DSC determination revealed that the melting temperature (T_m) of the PET component declined to some extent by comparison with neat PET. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3986–3993, 2007     

Phase structure and properties of poly(ethylene terephthalate)/high‐density polyethylene based on recycled materials

Blends based on recycled high density polyethylene (R‐HDPE) and recycled poly(ethylene terephthalate) (R‐PET) were made through reactive extrusion. The effects of maleated polyethylene (PE‐g‐MA), triblock copolymer of styrene and ethylene/butylene (SEBS), and 4,4′‐methylenedi(phenyl isocyanate) (MDI) on blend properties were studied. The 2% PE‐g‐MA improved the compatibility of R‐HDPE and R‐PET in all blends toughened by SEBS. For the R‐HDPE/R‐PET (70/30 w/w) blend toughened by SEBS, the dispersed PET domain size was significantly reduced with use of 2% PE‐g‐MA, and the impact strength of the resultant blend doubled. For blends with R‐PET matrix, all strengths were improved by adding MDI through extending the PET molecular chains. The crystalline behaviors of R‐HDPE and R‐PET in one‐phase rich systems influenced each other. The addition of PE‐g‐MA and SEBS consistently reduced the crystalline level (χ_c) of either the R‐PET or the R‐HDPE phase and lowered the crystallization peak temperature (T_c) of R‐PET. Further addition of MDI did not influence R‐HDPE crystallization behavior but lowered the χ_c of R‐PET in R‐PET rich blends. The thermal stability of R‐HDPE/R‐PET 70/30 and 50/50 (w/w) blends were improved by chain‐extension when 0.5% MDI was added. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A study of antimicrobial property of textile fabric treated with modified dendrimers

Dendrimers have been used as a vehicle to develop the antimicrobial properties of textile fabrics. We have taken advantage of the large number of functional groups present in the regular and highly branched three‐dimensional architecture of dendrimers. In this study, the poly(amidoamine) (PAMAM) G‐3 dendrimer was modified to provide antimicrobial properties. Following a procedure similar to what is suggested in the literature, PAMAM (G3) with primary amine end groups was converted into ammonium functionalities. The modification was then confirmed by FTIR and ¹³C‐NMR analysis. Dendrimers have unique properties owing to their globular shape and tunable cavities, this allows them to form complexes with a variety of ions and compounds; and also act as a template to fabricate metal nanoparticles. AgNO₃–PAMAM (G3) complex as well as a MesoSilver–PAMAM (G3) complex were formed and these modified dendrimers were characterized by a UV–Visible spectrophotometer to study the complex formation. Modified dendrimers were applied to the Cotton/Nylon blend fabric. SEM and EDX analysis were performed to study the dispersion of silver nanoparticles onto the fabric. An antimicrobial test of the treated‐fabric against Staphylococcus aureus exhibited significant biocidal activities for each type of modified‐dendrimer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study of the crystal structure of P(HBA/HNA)/PET blend fibers

The crystal structure of p‐hydroxybenzoate/2‐hydroxy‐6‐naphthoic acid copolyester [P(HBA/HNA)]/poly(ethylene terephthalate) (PET) blend (ACPET) fiber was studied with wide‐angle X‐ray diffraction and differential scanning calorimetry. The results showed that crystallites of P(HBA/HNA) and PET were formed in ACPET fibers; that is, some crystallites of ACPET fiber were composed of PET chains, and others were composed of P(HBA/HNA) chains. The thermal behaviors of the crystals of each component in the blend fiber were different from those of each corresponding pure component. For the fibers heat‐treated at 300 and 350°C, the degree of supercooling of P(HBA/HNA) segments in the blend fibers was the same as that of P(HBA/HNA) fiber, but the degree of supercooling of PET in the blend fibers was distinctly higher than that of pure PET fibers. Evidently, the aforementioned changes were attributable to the blending of PET with P(HBA/HNA). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 394–400, 2002     

PET纤维及其织物的阻燃技术进展

概述了聚对苯二甲酸乙二醇酯(PET)纤维及其织物的阻燃技术,包括共缩聚阻燃PET纺丝、PET与阻燃剂共混纺丝及PET织物阻燃后处理等。其中,阻燃剂主要有磷系及磷-氮系阻燃剂,如:9,10-二氢-9-氧杂-10-磷杂蒽-10-氧化物(DOPO)衍生物、次膦酸(酯)及其聚合物、氧化膦聚合物、膦酸酯及螺环磷酸酯等。今后应积极开发生态和环境兼容的阻燃PET纤维新技术。