多乙烯多胺桥联受阻酚类抗氧剂的合成及其清除DPPH·性能

以二乙烯三胺和三乙烯四胺为桥联基，β-(3,5-二叔丁基-4-羟基苯基)丙酰氯为抗氧化功能基团，通过酰胺化缩合反应合成了两类具有不同对位桥联基团的受阻酚类抗氧剂。采用傅里叶红外光谱和核磁共振氢谱证实了合成的多乙烯多胺桥联受阻酚类抗氧剂的化学结构。DPPH法研究了多乙烯多胺桥联受阻酚类抗氧剂清除自由基的性能，并探索了酚羟基个数和对位桥联基结构对受阻酚类抗氧剂清除自由基性能的影响。结果表明，多乙烯多胺桥联受阻酚类抗氧剂具有良好的清除DPPH·能力，且随着抗氧剂分子中酚羟基个数的增加，清除DPPH·的活性增加，分子中含有4个酚羟基的三乙烯四胺受阻酚类抗氧剂的抗氧化效率（AE）达到2.65×10^-2 L/(mol·s)。对位桥联基结构对受阻酚类抗氧剂清除DPPH·能力有较大影响，季戊四醇为桥联基的受阻酚类抗氧剂1010清除DPPH·能力最强，其抗氧化效率（AE）为3.08×10^-2L/(mol·s)；乙二胺为核的1.0代树枝状受阻酚类抗氧剂清除DPPH·能力最弱，其抗氧化效率（AE）为2.60×10^-2 L/(mol·s)。     

Antioxidation and mechanism of phosphites including the free phenolic hydroxyl group in polypropylene

Inhibiting the degradation of polypropylene (PP) in melt processing and usage is an important issue in the plastic industry. It is becoming more and more urgent to increase the antioxidation of phosphites alone while maintaining the water resistance. In this study, one phosphite antioxidant, named bis‐2,2′‐methyl‐4,6‐di‐tert‐butylphenyl phosphite (BM46TBPP), which contains a water‐resistant inner ring and a free phenolic hydroxyl group together, was synthesized. Then, antioxidation in PP was characterized with multiple extrusions and oxidation induction times (OITs). Finally, the hydrogen‐donating ability of this antioxidant was tested with 2,2‐diphenyl‐1‐picrylhydrazyl radical colorimetry to explain the antioxidation mechanism. The results show that the phosphite BM46TBPP displays better antioxidation than tris(2,4‐di‐tert‐butylphenyl) phosphite (Irgafos 168) in melt processing and OIT testing. Furthermore, the priority of this antioxidant was more obvious when it was used in the presence of oxygen, so the antioxidant even made the PP stabilized by it alone show a longer OIT value than the PP stabilized by the complex system including Irgafos 168 and 2,4‐di‐tert‐butylphenol because there was a free phenolic hydroxyl group in the BM46TBPP antioxidant molecule and the hydroxyl group made the antioxidant show intermolecular synergistic antioxidation through hydrogen donation to radicals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44696.     

Preparation and characterization of high melt strength polypropylene with long chain branched structure by the reactive extrusion process

The reactive extrusion of maleic anhydride grafted polypropylene (PP‐g‐MAH) with ethylenediamine (EDA) as coupling agent is carried out in a corotating twin‐screw extruder to produce long chain branched polypropylene (LCBPP). Part of PP‐g‐MAH is replaced by maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH) or linear low‐density polyethylene (LLDPE‐g‐MAH) to obtain hybrid long chain branched (LCB) polyolefins. Compared with the PP‐g‐MAH, PE‐g‐MAH, and their blends, the LCB polyolefins exhibit excellent dynamic shear and transient extensional rheological characteristics such as increased dynamic modulus, higher low‐frequency complex viscosity, broader relaxation spectra, significantly enhanced melt strength and strain‐hardening behaviors. The LCB polyolefins also have higher tensile strength, tensile modulus, impact strength and lower elongation at break than their blends. Furthermore, supercritical carbon dioxide (scCO₂) is constructively introduced in the reactive extrusion process. In the presence of scCO₂, the motor current of the twin extruder is decreased and LCB polyolefins with lower melt flow rate (MFR), higher complex viscosity and increased tensile strength and modulus can be obtained. This indicates that the application of scCO₂ can reduce the viscosity of melt in extruder, enhance the diffusion of reactive species, and then facilitate the long chain branching reaction between anhydride group and primary amine group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

桥键烷基酚及其衍生物用于合成橡胶防老剂的研究进展

分析了2,6-二叔丁基-4-甲基苯酚(BHT)作为合成橡胶防老剂存在易迁移、易挥发、抗老化效率低等问题,阐述了BHT与桥键烷基酚类防老剂的作用机理,介绍了桥键烷基酚类防老剂的优势、合成方法,指出用桥键烷基酚及其衍生物取代BHT是合成橡胶防老剂发展的方向.     

Photostabilization of styrene–ethylene–butylene–styrene block copolymer by hindered phenol and phosphite antioxidants

The photostabilization of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS), by hindered phenols and their combination with phosphite antioxidants has been studied by using a variety of spectroscopic methods including FTIR, UV, and luminescence spectroscopy coupled with crosslinking and hydroperoxide analysis. The addition of a hindered phenol was found to photostabilize the SEBS in terms of the inhibition of discoloration, and the formation of hydroperoxides, acetophenone, and oxidation products, as well as chain scission and disaggregation of the styrene units. Strong synergism was found with combinations of a hindered phenol and phosphite antioxidant, especially with an increase in the phosphite concentration. Residual titanium traces present as impurities in the material were found to play an important role in the photo‐oxidation of SEBS. Molecular weight appeared to be a determining factor in the proportion of chain scission/crosslinking reactions that occured. Nevertheless, the addition of antioxidants and the reduction of titanium content also proved satisfactory in stabilizing the low‐molecular‐weight material. J. VINYL. ADDIT. TECHNOL. 12:2–7, 2006. © 2006 Society of Plastics Engineers     

Effect of compatibilizer on morphology,thermal, and rheological properties of polypropylene/functionalized multi‐walled carbon nanotubes composite

Multi‐walled carbon nanotubes (MWCNTs) filled polypropylene (PP) composites were prepared by a corotating intermeshing twin screw extruder. To improve the dispersion of MWCNTs, the surface of MWCNT was modified with 1,10‐diaminodecane, and maleic anhydride grafted polypropylene (MA‐g‐PP) was used as a compatibilizer. Micrographs of well dispersed functionalized MWCNTs (diamine‐MWCNT) were observed due to the reaction between MA‐g‐PP and diamine‐MWCNT in PP/MA‐g‐PP/diamine‐MWCNTs composites. The different behaviors in crystallization and melting temperatures of PP/MA‐g‐PP/diamine‐MWCNTs composite were observed compared to PP and PP/neat‐MWCNT. Especially, the decomposition temperature of the composite was increased by 50°C compared to PP. PP/MA‐g‐PP/diamine‐MWCNTs composite showed the highest complex viscosity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Transferring noncharring polyolefins to charring polymers with the presence of Mo/Mg/Ni/O catalysts and the application in flame retardancy

This article presents a novel investigation on the Mo/Mg/Ni/O catalysts (Nmm‐cats) with which the noncharring polyolefins are basically transferred to the charring polymers under forced flaming conditions and the flame retardancy of polyolefins is improved dramatically. The results of model charring experiments show that when appropriate Mo/Mg/Ni molar ratio is adopted and only 3% Nmm‐cats is blended, the Nmm‐cats belong to high‐efficient charring catalysts that can deposit 56 and 64 wt % of volatile products in‐situ from linear low‐density polyethylene (LLDPE) and polypropylene (PP), respectively. The charring properties are characterized by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy; and the char‐forming mechanisms are analyzed by wide‐angle X‐ray diffraction experiment. The improvement in flammability properties for LLDPE and PP is demonstrated by using a cone calorimeter. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Structure–stability correlation of copolyimide membranes derived from aliphatic/alicyclic/aromatic diamine and aromatic dianhydrides

New polyamic acids with ‐A‐B‐A‐C‐ type periodic sequence of monomeric units (A derived from a diamine, B from benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride, and C from benzene‐1,2,4,5‐tetracarboxylic dianhydride) are prepared and transformed into polyimide membranes that are examined by various methods in order to investigate the influence of diamine units (aliphatic, alicyclic, or aromatic) on the morphology, thermal stability, and mechanical properties of membranes. Small‐ and wide‐angle X‐ray scattering and Atomic force microscopy show amorphous character of all membranes except for those containing hexane‐1,6‐diamine units. Thermogravimetric analysis reveals a decrease in the initial decomposition temperature from 551/501 °C to 437/395 °C (for N₂/O₂ atmosphere) when going from membranes with aromatic to those with aliphatic diamine units. Dynamic mechanical analysis shows quite high initial storage modulus (2100–3300 MPa) for all membranes at frequencies of 1, 10, and 20 Hz. The properties of prepared copolymeric polyimide are promising for a wide range of their potential technological applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45227.     

Development of nanofibrous morphology in LDPE/LLDPE/PP blends and its effect on mechanical properties of blend films

Nanofibrous morphology has been observed in ternary blends of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and isotactic polypropylene (PP) when these were melt‐extruded via slit die followed by hot stretching. The morphology was dependent on the concentration of the component polymers in ternary blend LDPE/LLDPE/PP. The films were characterized by wide angle X‐ray diffraction (XRD), scanning electron microscopy (SEM), and testing of mechanical properties. The XRD patterns reveal that the β phase of PP is obtained in the as‐stretched nanofibrillar composites, whose concentration decreases with the increase of LLDPE concentration. The presence of PP nanofibrils shows significant nucleation ability for crystallization of LDPE/LLDPE blend. The SEM observations of etched samples show an isotropic blend of LDPE and LLDPE reinforced with more or less randomly distributed and well‐defined nanofibrils of PP, which were generated in situ. The tensile modulus and strength of LDPE/LLDPE/PP blends were significantly enhanced in the machine direction than in the transverse direction with increasing LLDPE concentration. The ultimate elongation increased with increasing LLDPE concentration, and there was a critical LLDPE concentration above which it increased considerably. There was a dramatic increase in the falling dart impact strength for films obtained by blow extrusion of these blends. These impressive mechanical properties of extruded samples can be explained on the basis of the formation of PP nanofibrils with high aspect ratio (at least 10), which imparted reinforcement to the LDPE/LLDPE blend. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of high‐density polypropylene‐grafted polyethylene via a macromolecular reaction and its rheological behavior

High‐density polyethylene grafted isotactic polypropylene (PP‐g‐HDPE) was prepared by the imidization reaction between maleic anhydride grafted polyethylene and amine‐grafted polypropylene in a xylene solution. The branch density was adjusted by changes in the molar ratio between maleic anhydride and primary amine groups. Dynamic rheology tests were conducted to compare the rheological properties of linear polyolefins and long‐chain‐branched polyolefins. The effects of the density of long‐chain branches on the rheological properties were also investigated. It was found that long‐chain‐branched hybrid polyolefins had a higher storage modulus at a low frequency, a higher zero shear viscosity, a reduced phase angle, enhanced shear sensitivities, and a longer relaxation time. As the branch density was increased, the characteristics of the long‐chain‐branched structure became profounder. The flow activation energy of PP‐g‐HDPE was lower than that of neat maleic anhydride grafted polypropylene (PP‐g‐MAH) because of the lower flow activation energy of maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH). However, the flow activation energy of PP‐g‐HDPE was higher than that of PP‐g‐MAH/HDPE‐g‐MAH blends because of the presence of long‐chain branches. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polypropylene nanocomposite using maleated PP and diamine

The insertion of the aliphatic diamine inside the organoclay will help the dispersion of the clay platelets in the PP/clay nanocomposite due to the reaction between the maleated PP and the diamine. Cloisite®20A was just simply mixed with hexamethylene diamine (HMDA) under shearing condition in Brabender mixer. HMDA group was successfully penetrated into silicate layers. As a result of penetration, d‐spacing of organoclay was increased. Polypropylene/clay nanocomposites were prepared by compounding with maleated PP and amine‐treated clay. From the FTIR spectra, reaction between amine group and maleic‐anhydride group was confirmed. The effect of the organoclay on the properties of the nanocomposite such as the morphology, dynamic mechanical properties, crystal structure and crystallization behavior, glass transition temperature, thermal stability, and tensile properties were investigated and analyzed. Nanocomposites with amine‐treated clays show enhanced properties compared with those with non–amine‐treated clay (Cloisite®20A). From the TEM analysis, nanocomposites with amine‐treated clays shows better dispersibility compared with those with Cloisite®20A alone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of cross‐linked LLDPE/PP blend (LLDPE‐PP) as compatibilizer on morphology,crystallization behavior and mechanical property of LLDPE/PP blends

Moderate cross‐linked blend (LLDPE‐PP) of linear low‐density polyethylene (LLDPE) and polypropylene (PP) with benzoyl peroxide (BPO) were prepared by the reactive melt mixing in HAAKE mixer. Effect of LLDPE‐PP as compatibilizer on the morphology, crystallization behavior and mechanical properties of LLDPE/PP (87/13) blends were studied using scanning electron microscopy (SEM), polarized optical microscopy (POM), wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC) and mechanical testing machines. The results showed that LLDPE‐PP not only improved the interfacial adhesion between the LLDPE and PP but also acted as selective nucleating agent for crystal modification of PP. In the blends, the sizes of LLDPE and PP spherulites became smaller, and their melting enthalpies reduced in the presence of LLDPE‐PP. Furthermore, the mechanical properties of LLDPE/PP blends were improved with the addition of LLDPE‐PP, and when the concentration of LLDPE‐PP was 2 phr, the ternary blend had the best mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of biphenyl‐bridged,crosslinked polyalkoxysilanes: Determination of oil/organic solvent absorption features

A novel type of biphenyl‐bridged alkoxysilane‐based crosslinked polyalkoxysilane was prepared by the condensation of 4,4′‐bis(triethoxysilyl)?1,1′‐biphenyl and different lengths of linear aliphatic diols. Fourier transform infrared spectroscopy, solid‐state ¹³C and ²⁹Si cross‐polarization magic angle spinning nuclear magnetic resonance, and thermogravimetric analysis were used to characterize the biphenyl‐bridged, crosslinked polyalkoxysilanes. The crosslinked polymers were found to have very quick and high swelling capabilities in organic solvents and oils. The absorption–desorption kinetics and reusability features of the crosslinked polymers were also studied, and we found that the synthesized polymers reached their maximum absorption capacity during a variety of tests without losing capacity. We also tested the absorption performance of the sorbents from water surfaces. All of these results confirm that biphenyl‐bridged, crosslinked polyalkoxysilanes could be good candidates as sorbent materials for the cleaning of water from organic contaminants. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44193.     

聚烯烃的吹塑成型

聚烯烃(包括HDPE、LDPE、LLDPE、PP及EVA)是最多的一类吹塑级树脂。本文系统地分析各种吹塑级聚烯烃的性能、吹塑成型的机械设计要点、工艺条件及制品用途。     

Synthesis and fluorescence properties of aromatic‐aliphatic copolyamides

The aromatic‐aliphatic copolyamides were synthesized by condensation polymerization of aromatic diamine PPD (or APS, where PPD is p‐phenylene diamine and APS is aminophenyl sulfone), aliphatic diamine HDA (or EDA, where HDA is hexanediamine and EDA is ethylenediamine), and TPC (where TPC is terephthalyl chloride) with different molar ratios of aromatic diamine to aliphatic diamine. The steady‐state fluorescence of these condensed copolymers was investigated. These copolyamides exhibit strong blue‐to‐green fluorescence. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 315–321, 2005     

Synergistic profiles of chain‐breaking antioxidants with phosphites and hindered amine light stabilizers in styrene–ethylene–butadiene–styrene (SEBS) block copolymer

The photostabilization of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS) by phosphite/p‐hydroxybenzoate antioxidants and hindered phenol/hindered amine light stabilizers (HALS) was studied by using a variety of spectroscopic methods, including FTIR, UV, and luminescence spectroscopy coupled with crosslinking and hydroperoxide analysis. The results were compared with those obtained for hindered phenols and their combinations with phosphite antioxidants. All the stabilizing packages stabilized the SEBS in terms of the inhibition of discoloration and the formation of hydroperoxides, acetophenone, and oxidation products, as well as chain scission and disaggregation of the styrene units. Although phosphite/p‐hydroxybenzoate combinations appeared to reduce the formation of oxidation products, they did not show any remarkable enhancement in long‐term stabilization with respect to phenolic/phosphite antioxidants. On the other hand, strong synergistic profiles were found with the HALS. Mobility and diffusion impediments in the polymeric material appeared to play an important role in the stabilizing activity of the HALS. J. VINYL. ADDIT. TECHNOL. 12:8–13, 2006. © 2006 Society of Plastics Engineers     

Polymer processing and characterization of LLDPE films loaded with α‐tocopherol,quercetin, and their cyclodextrin inclusion complexes

Natural antioxidant additives were compounded into linear low‐density polyethylene (LLDPE) using a twin‐screw counter‐rotating mixer and compression molded into films. Manufactured LLDPE films contained 2715 mg kg^?1 α‐tocopherol in its free and β‐cyclodextrin complexed form and 1950 mg kg^?1 quercetin in its free and γ‐cyclodextrin complexed form. Both cyclodextrin complexes were loaded into films at 1.5% by weight. These natural antioxidants were incorporated into LLDPE resins with two different catalyst types, Ziegler‐Natta and metallocene. Films were characterized by optical microscopy, oxidation induction time (OIT), oxygen transmission rate, contact angle analysis, and atomic force microscopy (AFM). All antioxidant additives increased the oxidative stability of LLDPE as measured by increased OIT, particularly quercetin. Natural antioxidants and their cyclodextrin inclusion complexes may provide a dual function in packaging to protect the polymer from oxidative degradation during melt processing and to delay the onset of oxidation of the packaged food during storage. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

On the mechanism of compatibilization of polyolefin/liquid crystalline polymer blends with graft copolymers

The compatibilization mechanism of some compatibilizers for blends of polyolefins with a liquid crystalline polymer (LCP) was studied. Polyethylene (PE) and polypropylene (PP) were blended with a semirigid LCP (SBH) in a batch mixer, either with and without compatibilizers. The latter were two commercially available samples of functionalized polyolefins, that is, a PE‐g‐MA (HDM) and a PP‐g‐AA (Polybond 1001) copolymer and some purposely synthesized PE‐g‐LCP and PP‐g‐LCP copolymers. Microtomed films of the binary and the ternary blends were annealed at 240°C on the hot stage of a polarizing microscope and the changes undergone by their morphology were recorded as a function of time. The results indicate that the compatibilizers lower the interfacial tension, thereby providing an improvement of the minor phase dispersion. In addition to this, the rate of the coalescence caused by the high‐temperature treatment is appreciably reduced in the systems compatibilized with the PE–SBH and PP–SBH graft copolymers. Among the commercial compatibilizers, only Polybond 1001 displayed an effect comparable to that of the above copolymers. HDM improved the morphology of the as‐prepared PE blends, but failed to grant sufficient morphological stabilization against annealing‐induced coarsening. The results are discussed with reference to the chemical structure of the different compatibilizers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3027–3034, 2000     

Decoration of graphene oxide nanosheets with amino silane‐functionalized silica nanoparticles for enhancing thermal and mechanical properties of polypropylene nanocomposites

Graphene oxide nanosheets were decorated by amino‐silane modified silica nanoparticles. An electrostatic interaction between the negative charge of oxygen‐containing groups of graphene oxide and the positive charge of amino‐silane functional groups on the surface of silica nanoparticles plays a major role for the interfacial interaction of these two materials. The hybrid material was then used as a reinforcement in polypropylene (PP) composite. The increasing tensile strength at yield, tensile, and flexural modulus of the PP composite at a graphene oxide‐ amino‐silane silica loading content of 20 wt % are about 24.81, 55.52, and 30.35%, respectively, when compared with those of PP. It is believed that GO assists the dispersion of SiO₂ nanoparticles to the polymer matrix because of its unique structure having hydrophilicity due to its oxygen functional groups and hydrophobicity owing to its backbone graphitic carbon structure. This hybrid material may also be used as the reinforcement in other polyolefins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44382.     

Influence of the chemical structure of para-bridged group on the antioxidant behavior of hindered phenol antioxidants in HDPE resin

A hindered phenol antioxidant with rigid para-bridged group (antioxidant AP) was synthesized to study the effect of the chemical structure on the antioxidant properties of hindered phenol antioxidants in high density polyethylene (HDPE). Antioxidant behavior of series of hindered phenol antioxidants with different para-bridged groups in HDPE resin was also investigated by the thermal oxidation experiment, the mobility test, and the long-term accelerated thermal aging test. The results showed that the rigidity of para-bridged group and the molecule size have the important influences on the antioxidant performance of hindered phenol antioxidants in the HDPE resin, and the antioxidant abilities of antioxidant AP and Irganox 1,330 with the aryl para-bridged group was superior to Irganox 1,098 and 1.0G dendritic antioxidant with the alkyl para-bridged group at the same testing conditions. Compared with the hindered phenol antioxidants with alkyl para-bridged group, the hindered phenol antioxidants with aryl para-bridged group have better thermal oxygen stability and less mobility in the HDPE resin. Irganox 1,010 with ester groups is prone to hydrolysis to increase the mobility rate in hot water and the migration resistance of hindered phenol antioxidants in n-hexane. Moreover, the high content of phenolic OH group and the aryl para-bridged group are favorable for improving the antioxidant performance of hindered phenol antioxidants.