Fine dispersion of carbon black in fluorene‐based resin

The dispersion ability of fluorene‐based epoxy resin (FBE), bisphenol A based epoxy resin (PBE), fluorene‐based polyester (FBP), and polycarbonate (PC) in carbon black (CB) was evaluated. CB/FBE composite had a lower L value (reflectance, blackness) than that of CB/PBE composite, for the same CB content. Aggregations of CB in CB/FBE composites were much smaller than those in CB/PBE composites. The strong interaction between fluorene with cardo structure and CB resulted in a fine dispersion of CB in FBE. FBP had much higher dispersion ability of CB than PC. CB (50 wt%) was dispersed into FBP compared with the 10 wt% of CB dispersed in PC by melt blending. The effect of CB on the mechanical properties of FBP was much higher than that on PC due to fine dispersion of CB in FBP. The effect of CB addition on the T_g of FBP was also higher than that of CB on the T_g of PC. Computational simulation indicates that most stable energy between fluorene with a cardo structure and graphite structure was smaller than the energy between bisphenol A and graphite. It was also shown that the minimum energy appeared when the fluorene structure was almost parallel to the graphite plane. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Preparation and conductive properties of polycaprolactone‐grafted carbon black nanocomposites

Polycaprolactone‐grafted carbon black (CB‐g‐PCL) nanocomposites were prepared by surface‐initiated ring‐opening polymerization of ε‐caprolactone on the surface of CB. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), atomic force microscope (AFM), X‐ray diffraction (XRD), and polarizing optical microscope (POM) method were employed to characterize the resultant CB‐g‐PCL. The effect of temperature on resistivity of polycaprolactone‐grafted CB (CB‐g‐PCL) nanocomposites was investigated and compared with that of mixture of CB and PCL. It was found that CB‐g‐PCL nanocomposites exhibited positive temperature coefficient (PTC) phenomena between 48 and 51°C, and negative temperature coefficient (NTC) phenomena and between 51 and 54°C. The prepared CB‐g‐PCL nanocomposites have the potential to be temperature‐dependent switch materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of axial stretching on electrical resistivity of short carbon fibre and carbon black filled conductive rubber composites

The variation of electrical resistivity of carbon black and short carbon fibre (SCF) filled rubber composites was studied against the degree of strain at constant strain rate. It was found that both the degree of strain and strain rate affect the electrical resistivity of the composites. The change in resistivity against the strain and strain rate depends both on the concentration and the type of conductive filler. The incorporation of short carbon fibres (SCF) imparts higher conductivity to the composite than carbon black at the same level of loading. Composites filled with carbon black exhibit better mechanical properties than SCF filled composites. Electrical setting, ie a permanent change in electrical resistivity, was observed during extension–retraction cycles. A good correlation was found between the mechanical response and the electrical response towards strain sensitivity. The results of different experiments are discussed in the light of breakdown and formation of conductive networks in the filled rubber composites. © 2002 Society of Chemical Industry     

High transmittance and environment‐friendly flame‐resistant optical resins based on poly(methyl methacrylate) and cyclotriphosphazene derivatives

Highly transparent optical resins based on poly(methyl methacrylate) (PMMA) and two cyclotriphosphazene derivatives which acting as halogen‐free flame retardants were prepared. The refractive indices, visible light transmittance, water absorption, flame‐resistant characteristic, and the mechanical properties of the resins were studied. Comparing with pure PMMA, the as‐prepared resins with the two additives exhibited higher refractive index (n_d), longer UV cutoff wavelength and better surface hardness. The water absorption of the resins was decrease with increasing of the additives. The visible light transmittance of all the samples adding Additive A was higher than 90%. When the weight ratio of additive/MMA was 20/100, the limiting oxygen index (LOI) of the samples were 26 (with Additive A) and 22 (with Additive B), respectively. The surface hardness was increased from HB to 2H with increasing the content of the additives, and the impact and the tensile strength changed little for the formulas of the additives lower than 30% by weight. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

An environment‐friendly thermal insulation material from cellulose and plasma modification

Cellulose aerogels were prepared by combining the NaOH/thiourea/H₂O solvent system and the freeze‐drying technology. Hydrophobic aerogels were obtained with the cold plasma modification technology. The results showed that cellulose aerogel had good heat insulation performance, while the main factors affecting thermal conductivity were density and porosity. Thermal conductivity decreased with the decrease of density and the increase of porosity. It could be as low as 0.029 W/(m K). Cellulose aerogel adsorbed moisture easily. The moisture adsorption had a significant influence on the heat insulation performance of aerogel. After conducting hydrophobic modification using CCl₄ as plasma, cellulose aerogel was changed from hydrophilic to hydrophobic and water contact angle was as high as 102°. Hydrophobic modification did not affect the heat insulation performance of aerogel. This work provided a foundation for the possibility of applying cellulose aerogels in the insulating material field. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3652–3658, 2013     

Electrical resistivity of carbon black filled high‐density polyethylene composites

The electrical resistivity of high‐density polyethylene (HDPE) loaded with carbon black (CB) blends was evaluated as a function of the blending time and the melt index of HDPE. The relationship between the positive temperature coefficient effect and the room temperature volume resistivity was investigated. The positive temperature coefficient effect and reproducibility were improved significantly when the blending time of HDPE and CB was comparatively long. The effects of ⁶⁰Co γ‐ray and electron beam irradiation on the positive and negative temperature coefficient behavior of the blends were studied. The effect of thermal aging on the volume resistivity was studied to ascertain the structural stability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2440–2446, 2002     

Microstructural and mold resistant properties of environment‐friendly oil‐modified polyurethane based wood‐finish products containing polymerized whey proteins

Environmental concerns associated with the level of volatile organic compounds used in surface coatings have stimulated increased scientific research toward novel methods of developing environment‐friendly coatings. Prototype wood finish products containing polymerized whey proteins (PWP) were formulated. The microstructural characteristics of dry films prepared from environment‐friendly wood finishes containing PWP were examined using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The susceptibility of the coatings to microbial degradation was also examined using an accelerated mold test. AFM analysis revealed that increased addition of PWP resulted in films with increased surface roughness, decreased number of voids, and increased void size due to excessive aggregation among polymer components. CLSM analysis showed that the PWP distribution in the films is enhanced by homogenization of the coating mixes. There was no significant increase (P > 0.05) in mold growth between panels coated with finish containing PWP and those without PWP. Test panels coated with formulation containing PWP and low levels of biocide (0.3%) resulted in a significant decrease in mold growth in comparison to commercially available water‐based polyurethane coatings (P < 0.05). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3519–3530, 2006     

A study on environment‐friendly polymer gel for water shut‐off treatments in low‐temperature reservoirs

In this study, the zirconium acetate crosslinked gel systems are studied owing to their environment‐friendly and gelation performance in low‐temperature reservoirs through rheological measurements, environmental scanning electron microscopy, and scanning electron microscopy. The effects of various parameters on the gelation properties, stability, and microstructure in bottle test and porous media were addressed. With the increase of concentrations and temperature, gelation time is reduced and gel strength is increased. In addition, the gel systems show salt tolerance and shearing resistance. The environment‐friendly gel systems have a high stability in both injection water and formation water. A three‐dimensional network structure was formed in the gel and confirmed by environmental scanning electron microscopy. The three‐dimensional gel network was also formed in porous media, which bridges across the pore throats and reduced the water permeability in the formation. This study suggests that environment‐friendly polymer gels can be used for water shut‐off treatments in low‐temperature reservoirs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40154.     

Effect of some service conditions on the electrical resistivity of conductive styrene–butadiene rubber–carbon black composites

Conductive polymer composites were prepared using vulcanized styrene–butadiene rubber as a matrix and conductive carbon black as a filler. The filler loading was varied from 10 to 60 phr. The volume resistivity was measured against the loading of the carbon black to verify the percolation limit. The electrical conductivity of filled polymer composites is attributed to the formation of some continuous conductive networks in the polymer matrix. These conductive networks involve specific arrangements of conductive elements (carbon black aggregates) so that the electrical paths are formed for free movement of electrons. The effects of temperature and pressure on the volume resistivity of the composites were studied. The volume resistivity of all the composites increased with increase in temperature, and the rate of increase in the resistivity against temperature depended on the loading of carbon black. The change in volume resistivity during the heating and cooling cycle did not follow the same route, leading to the phenomena of electrical hysteresis and electrical set. It was found that the composites with 40 and 60 phr carbon black become more conductive after undergoing the heat treatment. Generally, all the composites showed a positive temperature coefficient of resistivity. The volume resistivity of all the composites decreased with increase in pressure. The relaxation characteristic of the volume resistivity of the composites was studied with respect to time under a constant load. It was found that the volume resistivity of the compressed specimen of the composites decreased exponentially with time. It was observed that initially a faster relaxation process and later a slower relaxation process occurred in these composites. Some mechanical properties of these composites were also measured to confirm the efficacy of these composites for practical applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2179–2188, 2004     

黑色耐磨防腐导电涂料的研制

利用有机硅树脂对环氧树脂进行改性,添加了一定量的纳米二硫化钼、纳米铝粉、导电碳黑和石墨,制作了一种黑色耐磨防腐导电涂料。实验表明,当有机硅树脂用量为12%,填料为8%,混合溶剂组成为m(丙酮):m(醋酸乙酯):m(醋酸丁酯):m(二甲苯)=2:1:1:1、用量为48%时,所得涂料耐磨性和防腐性能良好,涂层表面电阻达到了2.2×104?/cm2,具有较好的导电和防电磁性能。该涂料可以应用于陆军武器装备表面的电磁防护。     

Well‐defined,environment‐friendly synthesis of polypeptides based on phosgene‐free transformation of amino acids into urethane derivatives and their applications

In this study, both naturally occurring and artificial amino acids were successfully transformed into the corresponding urethane derivatives using diphenyl carbonate. The urethanes thus prepared could be efficiently cyclized into amino acid N‐carboxyanhydrides (NCAs) without the requirement of phosgene. In addition, the presence of primary amines converted the urethane derivatives into NCAs and initiated the ring‐opening polymerization of the in situ formed NCAs, allowing for the well‐defined synthesis of polypeptides. These polypeptides contained initiating ends functionalized by an amine‐derived residue and propagating ends bearing the reactive amino group. By precise control of the structures of the polypeptides, various polypeptide conjugates such as block copolymers and graft copolymers were successfully synthesized as designed, and their applications in antifouling coatings against proteins, drug delivery systems and biosensors were demonstrated. © 2019 Society of Chemical Industry     

Dielectric relaxation of conductive carbon black reinforced ethylene‐octene copolymer vulcanizates

The dielectric relaxation behavior of different conducting carbon black‐filled ethylene‐octene copolymer (EOC) vulcanizates prepared by melt‐mixing method has been studied as a function of frequency (100 Hz–5 MHz) over a wide range of temperatures (25–100°C). The effect of filler loading and frequency on AC conductivity, dielectric permittivity, impedance, and dielectric loss tangent (tanδ) has been studied. The nature of variation of the dielectric permittivity with the filler loadings was explained on the basis of interfacial polarization of the filler in the polymer matrix. The effect of filler loading on the real and complex part of the impedance was explained by the relaxation dynamics of the polymer chains in the vicinity of the fillers. The effect of filler and temperature on dielectric loss tangent, dielectric permittivity, AC conductivity, and Nyquist plot was also reported. The bound rubber (BR) value increases with increase in filler loading suggesting the formation of strong interphase, which is correlated with dielectric loss. Thermal activation energy (E_a) was found to be decreasing with the temperature, which follows the Arrhenius relation: τ_b = τ₀ exp(−E_a/K_BT) where τ_b is the relaxation time for the bulk material. From the plot of lnτ_b versus inverse of absolute temperature (1/T), the activation energies (E_a) were found to be 0.37 and 0.44eV, respectively. The percolation threshold was observed with 40 phr carbon black loading. POLYM. COMPOS., 37:342–352, 2016. © 2014 Society of Plastics Engineers     

Stretchable conductive films based on carbon nanomaterials prepared by spray coating

Stretchable conductive films consisting of a layer of carbon nanomaterials, that is, carbon nanotubes (CNTs), mechanically exfoliated graphene (GE), or chemically reduced graphene oxide (rGO), deposited on polydimethylsiloxane (PDMS) films were prepared by spray coating. The correlations among the concentration of the carbon nanomaterials, the electrical resistance and the optical transmittance of the spray‐coated films were investigated. The results show that the conductivity of the CNT coatings was better than that of the GE‐based coatings. When the CNT concentration of the dispersion for spraying increased from 0.01 to 0.075 mg/mL, the surface electrical resistance decreased from 7.8 × 10³ to 6.7 × 10² Ω, whereas for the GE or rGO coatings, the electrical resistance was several orders higher than that of the CNT coatings. The CNT spray‐coated films exhibited an optical transmittance of about 60% at a wavelength of 550 nm; this was higher than that of the GE or rGO spray‐coated films. The electric heating behaviors of the stretchable conductive films as functions of the applied voltage and the concentration of carbon nanomaterials and the electrical conductivity under tensile and bending strains were also investigated. The surface temperature of the CNT‐coated films rose rapidly up to 200°C within about 40 s when the applied voltage was 110 V. The stretchable conductive films have potential as electric heating elements because of their excellent conductive properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43243.     

Dispersion of carbon black in high‐abrasion furnace black filled nonsulfur modified powdered polychloroprene rubber

High‐abrasion furnace black (HAF, grade N330) filled nonsulfur modified powdered polychloroprene rubber [P(CR231/HAF)] was prepared with the method of carbon black–rubber latex coagulation using CR231 latex as raw rubber material, HAF as reinforcing filler, and polymeric resin as coating resin. The influence of the content of dispersing agent and coating resin on contact staining and dispersion properties of carbon black in P(CR231/HAF) were investigated. The results show that the addition of dispersing agent and coating resins can decrease the contact staining level of carbon black effectively. When the dispersing agent/HAF (w/w) ratio was 0.12 or 0.1, 10 phr coating resin was added, and P(CR231/HAF) without contact staining can be prepared. The analysis on scanning electron microscopy and surface energy spectrum showed that free carbon black crumb on the surface and inner of P(CR231/HAF) particles causes its contact staining. The well dispersion of carbon black in the P(CR231/HAF) can eliminate contact staining effectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 192–196, 2006     

Synthesis and characterization of palm‐based resin for UV coating

The production of UV curable acrylated polyol ester prepolymer from palm oil and its downstream products offer potential and promising materials for applications such as polymeric film preparation and coatings. In this study, palm olein polyol was reacted with acrylic acid in the presence of a catalyst and inhibitors via condensation esterification process. The reaction temperature of 80°C and the stirring rate of 400 rpm produce a homogeneous product. Based on iodine value result, the suitable amount of p‐toluene sulfonic acid monohydrate used as catalyst was 3.0% (w/w) of palm olein polyol. Different UV curable formulations have been investigated using the synthesized prepolymers with monomers and a small amount of photoinitiator. Monomers used were 1,6‐hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate (TMPTA) while photoinitiator used was 1‐hydroxy cyclohexyl phenylketone (Irgacure 184). The mixtures were cured to make thin polymeric films under UV radiation with doses between 2 and 14 passes (energy per pass is 0.6 J/cm²). Coating and curing was carried out on glass for pendulum hardness and FTIR analysis. Pendulum hardness of the film prepared using monomer HDDA and the prepolymer previously synthesized using 3.0% catalyst was 24.5%. The radiation dose needed was 14 passes. The highest pendulum hardness of 49.4% was achieved using monomer TMPTA and the prepolymer synthesized using 2.0% catalyst. The radiation dose needed was 10 passes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and performance measurement of environment‐friendly solidified dust suppressant for open pit coalmine

In this work, a new type of environment‐friendly solidified dust suppressant was developed to solve the dust pollution problem in open pit coalmines, coal bunkers, and so on. Natural polymer chitosan with excellent properties was chemically modified. Infrared spectroscopy was adopted to characterize the product. Using substitution rate as the evaluating indicator, the optimized mass ratio between monomer 3‐chloro‐2‐hydroxypropyl trimethyl ammonium chloride and chitosan, reaction temperature, reaction time, and pH were determined via single factor experiments. Combining the results of the four‐factor‐four‐level orthogonal experiment, the optimum reaction conditions A₂B₃C₄D₃ were obtained. The hardened film on the surface of coal powders was observed by high‐resolution scanning electron microscope. In addition, the water retention, solidification performance, and wind erosion resistance of the dust suppressant, as well as its influence on coal properties were measured. The results show that the synthesized dust suppressant demonstrates excellent properties and has good dust suppression effect. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46505.     

环保型木薯淀粉接枝丙烯酸共聚物的合成研究

以N,N'-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,采用水溶液聚合法制备了木薯淀粉接枝丙烯酸高吸水性树脂.考察了淀粉含量、中和度、引发剂用量、交联剂用量等因素对反应的影响.结果表明:在木薯淀粉含量为10%,引发剂用量为0.3%,交联剂用量为0.025%,丙烯酸与氢氧化钠的中和度为85%的条件下,制备得到的吸水性树脂吸水率达1355 g·g-1,其吸水速率快、加压保水能力强、热稳定性好.     

Resistivity relaxation behavior of carbon black filled high‐density polyethylene conductive composites

The variation of resistivity for high‐density polyethylene (HDPE) conductive composites filled with carbon black (CB) with time was investigated under the excitation of different temperature field. The movement of CB particles in the HDPE matrix was not a momentary equilibrium process, but a relaxation process. The relaxation of resistivity of the composites was monotonic, and it could be described by an exponential form above melting temperature. However, the relaxation of resistivity was nonmonotonic below melting temperature, herein a parameter t₀ which was the beginning time of the resistivity attenuation could be introduced into the exponential equation. The attenuation of resistivity at constant temperature was limited for the composites with certain content of CB. The resistivity of the composites would incline to a constant value with the prolongation of time no matter what the heat treatment temperature was. Heating rate had influence on the relaxation of resistivity of the composites, and the lower heating velocity resulted in less time to approach to the equilibrium resistivity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

炭黑在锡偶联型 SSBR中的分散性

通过与ESBR做对比,对锡偶联型SSBR的的炭黑分散性作了研究。Payne效应、电阻率及透射电子显微镜3种方法均证明锡偶联型SSBR的炭黑分散性比ESBR 1502高,说明锡偶联结构有助于炭黑的高度分散,从而使胶料生热大幅降低。     

High thermal conductive m‐xylylenediamine functionalized multiwall carbon nanotubes/epoxy resin composites

In this study, multiwall carbon nanotubes (MWNTs) functionalized by m‐xylylenediamine is used as thermal conductive fillers to improve their dispersibility in epoxy resin and the thermal conductivity of the MWNTs/bisphenol‐A glycidol ether epoxy resin composites. Functionalization with amine groups of MWNTs is achieved after such steps as carboxylation, acylation and amidation. The thermal conductivity, impact strength, flexural strength, and fracture surfaces of MWNTs/epoxy composites are investigated with different MWNTs. The results show that m‐xylylenediamine is successfully grafted onto the surface of the MWNTs and the mass fraction of the organic molecules grafted onto MWNTs is about 20 wt %. The thermal conductivity of MWNTs/epoxy composites is further enhanced to 1.236 W/mK with 2 wt % m‐MWNTs. When the content of m‐MWNTs is 1.5 wt %, the impact strength and flexural strength of the composites are 25.85 KJ/m², 128.1 MPa, respectively. Scanning electron microscope (SEM) results show that the fracture pattern of composites is changed from brittle fracture to ductile fracture. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41255.