Optimization of synthesizing leucine-binding nano-sized magnetite by a two-step transformation

The optimum conditions for synthesizing leucine (Leu)-binding nano-sized magnetite (NSM) particles by a two-step transformation (TST) process were studied. The formation and magnetization of as-synthesized NSM particles were investigated through variation of the acidity, the type of surface modifier, and the nature of the acid for pH adjustment. With increased acidity, the saturation magnetization of the NSM particles decreased, but the amount of Leu coated on the surface of NSM particles increased. After the influence of hydroxyl (OH⁻) groups on the surface of NSM particles was removed by using the dicarboxyl anion (C₂O₄²⁻) as a ligand in the first step, Leu was successfully bound with NSM particles in the second step. However, when polyethylene glycol (PEG) was used as a surface modifier, it was difficult to form the Leu-to-NSM particle complex. In terms of the acid used to modify pH, H₂SO₄ was slightly less effective than HCl in achieving saturation magnetization because the coordination for SO₄²⁻ anions is stronger than that of Cl⁻ anions. The preparation of other amino acid-binding NSM particles can be optimized in an analogous manner.     

环氧官能化ABS增韧PBT树脂的性能研究

采用乳液聚合方法合成了甲基丙烯酸环氧丙酯(GMA)共聚的丙烯腈/丁二烯/苯乙烯核壳粒子ABS-g-GMA,用于不同分子量聚对苯二甲酸丁二醇酯(PBT)的增韧。红外光谱证明GMA接枝共聚到了ABS粒子上。DMA测试发现PBT与ABS、ABS-g-GMA之间有一定的相容性。SEM表明ABS-g-GMA均匀分散在不同分子量的PBT树脂中。ABS-g-GMA可以实现对PBT树脂的有效增韧,PBT树脂的分子量越大,增韧效率越高,共混物的断裂伸长率越大。     

Enhanced interfacial adhesion in carbon fiber/poly (acrylonitrile‐butadiene‐styrene) composite through fiber surface treatment by an emulsion sizing

To improve the interfacial adhesion between carbon fiber (CF) and poly(acrylonitrile‐butadiene‐styrene) (ABS) thermoplastic, an emulsion sizing whose film former was a terpolymer N‐phenylmaleimide‐styrene‐maleic anhydride (NSM)/ABS mixture was prepared. NSM, an efficient heat‐resistant modifier for ABS, could make the film former possess a superior heat resistance, which helped the sizing layer maintain integrity during the preparation of CF/ABS composite. Moreover, differential scanning calorimetry (DSC) results demonstrated that the glass transition temperature (T_g) of the NSM modified ABS achieved an improvement of 25.3°C. Particle size and distribution of the sizing agent were investigated to evaluate its stability. The FTIR spectrum obtained demonstrated that the chemical compositions of the sized CF got greatly changed and numerous functional groups appeared on sized CF. Abrasion resistance and fluffs of CF were tested and the results indicated that the sized CF obtained an appreciable enhancement in handleability. Interlaminar shear strength (ILSS) results revealed, after sizing, that the ILSS enhanced by 26.6%, due to the inserted sizing layer between CF and ABS matrix. POLYM. COMPOS., 37:2940–2949, 2016. © 2015 Society of Plastics Engineers     

Polylactide toughening with epoxy‐functionalized grafted acrylonitrile–butadiene–styrene particles

Glycidyl methacrylate functionalized acrylonitrile–butadiene–styrene (ABS‐g‐GMA) particles were prepared and used to toughen polylactide (PLA). The characteristic absorption at 1728 cm^?1 of the Fourier transform infrared spectra indicated that glycidyl methacrylate (GMA) was grafted onto the polybutadiene phase of acrylonitrile–butadiene–styrene (ABS). Chemical reactions analysis indicated that compatibilization and crosslinking reactions took place simultaneously between the epoxy groups of ABS‐g‐GMA and the end carboxyl or hydroxyl groups of PLA and that the increase of GMA content improved the reaction degree. Scanning electron microscopy results showed that 1 wt % GMA was sufficient to satisfy the compatibilization and that ABS‐g‐GMA particles with 1 wt % GMA dispersed in PLA uniformly. A further increase of GMA content induced the agglomeration of ABS‐g‐GMA particles because of crosslinking reactions. Dynamic mechanical analysis testing showed that the miscibility between PLA and ABS improved with the introduction of GMA onto ABS particles because of compatibilization reactions. The storage modulus decreased for the PLA blends with increasing GMA content. The decrease in the storage modulus was due to the chemical reactions in the PLA/ABS‐g‐GMA blends, which improved the viscosity and decreased the crystallization of PLA. A notched impact strength of 540 J/m was achieved for the PLA/ABS‐g‐GMA blend with 1 wt % GMA, which was 27 times than the impact strength of pure PLA, and a further increase in the GMA content in the ABS‐g‐GMA particles was not beneficial to the toughness improvement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

ABS树脂的性能与形态结构设计 ⅠSAN在PB橡胶粒子上接枝率的控制及其对ABS树脂结构和性能的影响

采用种子乳液聚合技术在聚丁二烯乳胶粒上接枝共聚苯乙烯和丙烯腈 ,通过改变共聚单体和聚丁二烯的投料比合成了一系列PB g SAN共聚物 ,将这些共聚物与SAN树脂进行熔融共混制得了ABS树脂。研究了投料比对SAN在PB上的接枝率、SAN的分子量和ABS树脂的形态结构及性能的影响。结果发现 ,随着投料比的增加 ,SAN在PB上的接枝率及SAN的分子量提高 ,接枝率和SAN分子量共同作用影响着ABS树脂的冲击韧性和加工性能。形态结构研究结果表明 ,投料比不仅影响着橡胶粒子在SAN基体中的分散程度 ,而且影响着橡胶粒子的内部结构 ,随着投料比的增加 ,橡胶粒子在基体中的分散程度提高 ,其内部的包容结构增多并导致了橡胶粒子粒径的增大。     

Structure and properties of heat‐resistant ABS resins innovated by NSM random copolymer

N‐phenylmaleimide(NPMI)‐styrene(St)‐maleic anhydride (MAH) copolymer was synthesized in xylene solution by one‐step free radical copolymerization, using di‐tert‐butyl diperoxyterephthalate as initiator. The resulting heat‐resistant NPMI‐St‐MAH (NSM) copolymer was characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography, differential scanning calorimetry, elemental analysis, and nuclear magnetic resonance spectroscopy (¹H‐NMR and ¹³C‐NMR). The results show that NPMI‐St‐MAH exhibits a random sequence distribution with a NPMI: St: MAH weight ratio of 47:51:2. The glass transition temperature (T_g) is about 190.0°C. Blends of acrylonitrile‐butadiene‐styrene (ABS) with various contents of NSM were prepared using a twin‐screw extruder, and the effects of NSM content on the thermal and mechanical properties of ABS blends were investigated. It was found that the Vicat softening point, tensile strength, flexural strength, flexural modulus, and Rockwell hardness of the ABS/NSM blends were all significantly enhanced with increasing NSM content, whereas the impact strength shows the opposite trend. The impact fracture surface morphology was characterized by scanning electron microscope. It was revealed that cavitation and cavity coalescence resulted in the toughening of the material, which well accounts for the decrease of impact strength with increasing NSM content. In addition, the rheological properties of the blends were examined using a capillary rheometer. The blends present excellent processing property and are suitable for injection molding, although a pseudoplastic behavior was observed in all cases. POLYM. COMPOS., 34:920–928, 2013. © 2013 Society of Plastics Engineers     

原位反应增容无机非卤阻燃ABS微观结构研究

利用扫描电镜对原位反应增容技术制各的无机非卤阻燃ABS母粒及材料的界面形态进行了系统研究，考察了无机非卤阻燃剂与ABS树脂间的相容性。结果表明：采用该法制得的无机非卤阻燃ABS材料阻燃剂粒子被基体树脂包覆后均匀地分散在ABS树脂中，很难看出阻燃剂与ABS之问明显的界面，断裂截面显示出韧性断裂的基本特征，无机非卤阻燃剂与ABS良好的相容性是母粒法加工技术和原位反应增容技术共同作用的结果。     

橡胶粒子粒径对ABS树脂结构与性能的影响

采用乳液技术在聚丁二烯(PB)和丁苯橡胶(SBR)乳胶粒子上接枝共聚苯乙烯和丙烯腈合成了PB质量分数为60％的ABS接枝粉料,将其与苯乙烯-丙烯腈共聚物(SAN树脂)熔融共混获得了一系列不同组成和结构的丙烯腈-丁二烯-苯乙烯共聚物(ABS树脂),研究了橡胶粒子粒径对ABS树脂的形态结构、力学性能的影响.结果表明,PB和SBR橡胶粒子的粒径分别为0.3μm和0.05 μm左右时,橡胶粒子的粒径对ABS树脂力学性能的影响十分显著.单独采用小拉径SBR橡胶粒子不能有效地增韧SAN树脂,而大粒径PB橡胶粒子对SAN树脂具有良好的增韧效果.     

ABS/蒙脱土纳米复合材料的制备、结构及性能

将SAN／蒙脱土纳米复合材料与ABS高胶粉熔融共混得到ABS／蒙脱土纳米复合材料。对纳米复合材料的机械性能进行了表征．结果发现蒙脱土的加入一定程度上提高了ABS的杨氏模量和弯曲模量，但冲击强度有明显的降低。采用XRD、TEM和SEM对纳米复合材料的结构进行表征，结果表明在共混过程中，蒙脱土片层的物理特性导致其基本分布在橡胶粒子的表面．甚至造成粒子的变形和破裂；ABS／蒙脱土纳米复合材料在冲击过程中，蒙脱土片层的分散状态导致橡胶粒子不能发生塑性变形，冲击断面呈多孔形态。     

PVC/SAN/ABS共混物的增韧机理

采用以乳液聚合的方法合成丙烯腈-丁二烯-苯乙烯共聚物(ABS)接枝粉料,将其与PVC、苯乙烯/丙烯腈共聚物（SAN）树脂熔融共混制备PVC/SAN/ABS共混物。恒定共混物中ABS含量,改变体系中SAN与PVC的比例从70.5/17.5至18/70。TEM分析表明,当共混物中SAN含量较多时,可以观察到银纹的存在;当共混物中PVC含量较多,可以观察到剪切屈服的发生;SEM分析发现,当共混物中PVC含量较多时,断裂表面出现了大量的空洞并伴随着基体的塑性流动;SAXS分析表明,当共混物中SAN的含量较多时,散射强度的增加是银纹的贡献能力增大的结果。     

Poly(styrene-co-acrylonitrile)/montmorillonite organoclay mixtures: a model system for ABS nanocomposites

Dispersion of clay particles in acrylonitrile-butadiene-styrene (ABS) and styrene-acrylonitrile copolymer (SAN) nanocomposites with montmorillonite (MMT) have been compared to assess whether ABS/MMT nanocomposite behavior can be adequately modeled using the simpler SAN/MMT system. Electron microscopy photomicrographs show that clay particles in ABS/MMT composites reside in the SAN matrix phase and accumulate at the rubber particle surfaces. In mixtures of four organoclays with the two polymers, WAXS (wide angle X-ray scattering) peak height and shift in gallery height was the same for a given organoclay. Aspect ratios determined through image analysis were also the same in each polymer. Modulus enhancement as measured by an exfoliation efficiency index showed the same patterns for each organoclay in the two matrices, but the ABS/MMT composites had consistently lower efficiencies than in SAN/MMT composites. This trend is expected to be due to the variations in orientation of clay particles in ABS/MMT composites at the rubber particle surface. In summary, SAN/MMT composites represent a good model system for ABS/MMT.     

Influence of the tert‐dodecyl mercaptan content in poly(acrylonitrile‐butadiene‐styrene) on properties of chlorinated polyvinyl chloride/poly(acrylonitrile‐butadiene‐styrene) blends

A series of poly(acrylonitrile‐butadiene‐styrene) (ABS) grafting modifiers were synthesized by emulsion grafting poly(acrylonitrile‐styrene) (SAN) copolymer onto polybutadiene (PB) latex rubber particles. The chain transfer reagent tert‐dodecyl mercaptan (TDDM) was used to regulate the grafting degree of ABS and the molecular weight of SAN copolymers. By blending these ABS modifiers with Chlorinated polyvinyl chloride (CPVC) resin, a series of CPVC/ABS blends were obtained. The morphology, compatibility, and the mechanical properties of CPVC/ABS blends were investigated. The scanning electron microscope (SEM) studies showed that the ABS domain all uniformly dispersed in CPVC matrix. Dynamic mechanical analyses (DMA) results showed that the compatibility between CPVC and SAN became enhanced with the TDDM content. From the mechanical properties study of the CPVC/ABS blends, it was revealed that the impact strength first increases and then decreases with the TDDM content, which means that the compatibility between CPVC and the SAN was not the only requirement for maximizing toughness. The decreasing of tensile strength and the elongations might attribute to the lower entanglement between chains of CPVC and SAN. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Morphology,thermal, and mechanical properties of acrylonitrile–butadiene–styrene/carbon black composites

Acrylonitrile–butadiene–styrene (ABS) polymers are susceptible to degradation that increases the yellowness of the polymer, distorts the surface glossy, and affects the mechanical properties. One way to protect ABS against degradation is the addition of carbon black (CB) that can act as a stabilizer. In this work, CB was dispersed in ABS through melt‐compounding. Electron microscopy was used to study the morphology of the filled‐ and unfilled‐ABS, and revealed that the CB particles/aggregates were distributed within the styrene–acrylonitrile (SAN) phase and around the PB phase. The results of the Fourier transform infrared spectroscopy showed that upon processing of ABS, crosslinking in the polybutadiene (PB) phase was the governing degradation mechanism. Increasing the CB content resulted in increasing the heat stability of the ABS/CB compounds, which was confirmed by thermogravimetric analysis. The DTA results showed that the PB degradation peak occurring at about 395°C was disappeared by addition of CB. Impact strength test was performed to study the effect of CB on the toughness of ABS. Impact strength was reduced with increasing CB loading. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Ultrasound Irradiation Coating of Silver Nanoparticle on ABS Sheet Surface

Ultrasound irradiation was used for anchoring silver nanoparticles with an average size from 10 to 50 nm onto the surface of acrylonitrile–butadiene–styrene (ABS) sheets 1 mm thick. The sonochemical reduction was carried out under argon at room temperature. Silver nanoparticles were obtained and deposited on the ABS surface by the irradiation of a mixture containing ABS plaques, silver nitrate (AgNO₃), ethylene glycol and water. Reaction conditions such as temperature, AgNO₃ concentration and irradiation time were controlled to achieve the deposition of silver nanoparticles onto the surface of ABS sheets. Nano silver coated ABS samples were characterized by X-ray diffraction, transmission and scanning electron microscopy, Raman spectroscopy and antimicrobial activity, specifically against the fungus, Aspergillius niger, and the bacterium, Escherichia coli. The observed results may be applied in the design of industrial ABS sheets with antimicrobial characteristics.     

Effect of reactive group types on the properties of core-shell modifiers toughened PA6

Summary  Reactive monomers such as acrylic acid (AA), maleic anhydride (MA) and glycidyl methacrylate (GMA) were grafted onto acrylonitrile-butadiene-styrene core-shell copolymer (ABS) by emulsion polymerization method. These functionalized ABS were used to toughen PA6. FTIR and Molau tests showed that these monomers were introduced onto ABS copolymers and compatibilization reactions took place between PA6 and the AA, MA and GMA grafted ABS. TEM result showed that the modified ABS copolymer dispersed in PA6 matrix uniformly and no obvious difference could be found between the different PA6 blends. However, mechanical test showed that GMA and MA modified ABS achieved much better toughening effect than the AA grafted ABS copolymer due to the stronger interfacial reactions. Fracture characterization indicated that PA6 toughened with GMA and MA modified ABS showed higher G_ivalues according to the Vu-Khanh approach and much obvious shear yielding in the deformed zone could be found.     

环氧官能化ABS增韧PBT及其共混物

合成了甲基丙烯酸环氧丙酯(GMA)接枝的丙烯腈-丁二烯-苯乙烯(ABS-g-GMA)核壳粒子增韧聚对苯二甲酸丁二醇酯(PBT),加入环氧树脂(Epoxy)为扩链剂进一步提高共混物的性能。红外光谱(FTIR)结果表明:GMA成功接枝到ABS粒子上;研究发现不同GMA含量的ABS-g-GMA粒子在PBT及PBT/Epoxy共混物中均匀分散;ABS-g-GMA对PBT增韧效果较好,Epoxy进一步提高了PBT/ABS-g-GMA共混物的冲击韧性及拉伸强度;ABS-g-GMA增韧PBT的机理是橡胶粒子的空洞化和PBT基体的剪切屈服。     

Investigation of the rheological behavior of titanium dioxide pigmented acrylonitrile–butadiene–styrene polymer

Titanium dioxide (TiO₂) pigments may be surface‐modified by hydrous oxides, such as alumina (e.g., Cristal 134) or by organic compounds, such as organophosphate (e.g., Tiona 188). In this investigation, the effects of these pigments on the rheological properties of acrylonitrile–butadiene–styrene (ABS) polymer were investigated. With the oscillatory rheometry method in the linear viscoelastic region, the storage and loss moduli versus frequency graph of ABS in the molten state showed two crossover points (COPs) when the surface of the ABS components, that is, poly(styrene‐stat‐acrylonitrile) and poly[(styrene‐stat‐acrylonitrile)‐graft‐polybutadiene] or g‐ABS, had good interaction. The first COPs increased when the TiO₂ content rose to 0.5 and 1.5% in Tiona 188 and Cristal 134 pigmented ABS samples, respectively. With the addition of TiO₂ up to these contents, the polymer–pigment interaction becomes stronger so that the dispersion of the pigments was good. With increasing TiO₂, the first COPs dramatically decreased because of agglomeration of the pigments. The shifting of the first COP may be applied as a criterion to specify the dispersion of TiO₂ particles in the ABS matrix. Scanning electron micrographs showed that the pigments had no effect on the size of the polybutadiene particles. Also, transmission electron micrographs proved that agglomerates of Tiona 188 and Cristal 134 particles were formed above 0.5 and 1.5% TiO₂ contents, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Structure-property relationships in polyamide/acrylonitrile-butadiene-styrene (ABS) blends

The structures and physical properties of four blends of poly(acrylonitrile-co-styrene-g-butadiene) (ABS) materials with polycaprolactam (PA6) have been characterized. The blends were separated into components by selective solvent extraction and were found to contain different structures: Blend A contained no PA6 grafts. Blend B contained PA6 grafted onto both soluble and insoluble ABS. Blend C contained PA6 grafted onto soluble poly(styrene-co-acrylonitrile) (p-SAN). In Blend D, PA6 was grafted onto both the insoluble ABS and the p-SAN phases. Transmission electron microscopy showed different morphologies in the blends. Blend A had a co-continuous, somewhat laminar structure, while Blend D consisted of an ABS phase dispersed in a PA6 continuum. Blends B and C had intermediate structures. All four blends, however, had very similar rheological and physical properties despite the variation in structure.     

影响苯乙烯丙烯腈在聚丁二烯乳胶粒上接枝共聚反应的因素

采用种子乳液聚合技术在聚丁二烯 ( PB)乳胶粒上接枝共聚苯乙烯 ( St)和丙烯腈 ( AN) ,合成了一系列 PB-g-SAN共聚物 ( ABS)。将这些共聚物用丙酮溶解并在超速离心机上将 PB-g-SAN和未接枝在 PB上的游离 SAN分离 ,计算出 SAN在 PB上的接枝率和接枝效率。通过改变共聚单体的组成和加料时间 ,研究了接枝率和接枝效率的变化。结果表明 SAN的接枝率随着 PB含量的增加而降低 ,在共聚单体中增加引发剂 ( CHP)和分子量调节剂 ( TD-DM)的含量 ,SAN在 PB上的接枝率和接枝效率表现出了下降的趋势 ,而共聚单体的配比 St/ AN和加料时间对接枝率和接枝效率的影响不大。     

Viscoelastic,mechanical, and thermal characterization of fly ash‐filled ABS composites and comparison of fly ash surface treatments

In the present investigation, viscoelastic, mechanical, thermal properties, and microstructural analysis of ABS reinforced with various surface treated fly ash (FA) has been studied. FA particles were surface treated with various chemical reagents, i.e., Ca(OH)₂, NaOH, and Bis(3‐triethoxysilylpropyl)tetrasulfane (Si69) to improve the interfacial adhesion between ABS and FA. DMA tests confirmed an increase in the stiffness in the surface treated composites. Hybrid ABS/FA composites showed optimum storage modulus and T_g as compared with the virgin matrix. TGA analysis also showed higher thermal stability of ABS/FA composites than virgin matrix with the surface treatments of FA. The treated FA composites also show improved mechanical properties compared to untreated FA composite. The morphology of virgin matrix, untreated and treated FA composites was studied employing SEM. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers