Acrylonitrile Composites Research Articles

Kenaf fiber reinforced chemically functionalized styrene-acrylonitrile composites

In view of no reports on natural fiber reinforced functionalized styrene acrylonitrile composites, this study develops kenaf fiber (KNF) reinforced chemically functionalized styrene acrylonitrile (CF-SAN) composites (KNF/CF-SAN) by extrusion and injection molding. The selected CF-SAN matrix is a chemically functionalized random ter-polymer, with high (10 ± 2%) maleic anhydride functionality and requires higher processing temperature. With respect to CF-SAN, the 10/90, 20/80 and 30/70 KNF/CF-SAN composites show 25%, 46% and 75% higher tensile modulus, 23%, 55% and 78% higher tensile strength, 34%, 66% and 104% higher flexural modulus and 48%, 87% and 125% higher flexural strength. Relative to the dry matrix, the water absorbed composites show higher properties, but relative to the respective dry composites, the water absorbed composites have at least 7% lower tensile strength and at least 20% lower tensile modulus, flexural modulus and flexural strength. SEM and FTIR (ATR-IR) establish that hydrogen bonding and esterification by Palsule process impart CF-SAN/KNF adhesion and bonding in the composites. The composites show thermal stability between KNF reinforcement and CF-SAN matrix upto 295°C.

Effect of core–shell structured SiO2@MoS2 on the tribological properties of epoxy resin/carboxyl terminated butadiene acrylonitrile composites

AbstractTowards the goal of improving the tribological properties of epoxy‐based composites, epoxy resin was firstly modified with carboxyl terminated butadiene acrylonitrile (CTBN), and then further modified by core–shell structured of SiO2@MoS2 fillers. The friction and wear properties of studied composites were tested on a Plate‐on‐Ring configuration under different loads and speeds. To reveal the tribological contribution of MoS2 and SiO2 in the hybrid fillers, tribo‐tests were also done on composites filled with single CTBN, MoS2 and SiO2. It is revealed that the transfer of both the EP/CTBN matrix and SiO2@MoS2 CSs fillers play an important role in governing the tribo‐properties of rubber toughened EP composites. Depending on contacting conditions, the SiO2@MoS2 CSs fillers might be released into the sliding interface and tribo‐chemical reactions might take place, both of which helped improve the tribo‐properties of studied composites.

Vapor Phase Modification for Selective Enrichment of Grafted Styrene/Acrylonitrile onto Carbon Nanotubes Via ATRP

Nitric acid vapor phase oxidation of multi-walled carbon nanotubes (MWCNTs) was proposed as a promising technique to fabricate poly styrene-co-acrylonitrile (SAN)-grafted-CNTs via atom transfer radical polymerization (ATRP). The in-situ ATRP grafting approach was successfully employed to graft polystyrene (PS), SAN and polyacrylonitrile (PAN), onto the convex surfaces of pristine MWCNTs (PCNT) and acid-functionalized MWCNTs (FCNT). Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and thermogravimetric analysis (TGA) confirmed the effectiveness of the modification via the ATRP grafting approach. The molar composition of acrylonitrile in the synthesized copolymer on the surface of CNTs for an FCNTs was calculated to be about 80% and 67.5% by 1H-NMR and TGA respectively, whereas the value is lower for PCNTs. Morphological studies showed that SAN-grafted FCNTs exhibit rougher surface morphology compared to the SAN-grafted PCNTs. Moreover, the higher diameter of the FCNTs indicated the higher polymer content, which was coated onto CNTs functionalized by vapor-phase oxidation. Therefore, the vapor phase oxidation strategy employed in this study could be utilized as a general method to prepare CNTs which can serve as an ATRP macroinitiator for the fabrication of various polymer grafted CNTs.

Thermal aging and chemical resistance evaluation of carbon black filled natural rubber blending: effect of the composition of acrylo nitrile and styrene butadiene rubber

Natural rubber (NR) has excellent tensile and abrasion properties, but its thermal and chemical resistance needs to be improved. The present study investigates the effect of acrylonitrile-butadiene rubber (NBR) and styrene-butadiene rubber (SBR) composition in NR compounding filled carbon black (CB). The effect of chemical and heat resistance was examined by varying the addition of SBR/NBR (phr/phr) as follows 40/0; 35/5; 30/0; 25/15; and 20/20 into 60 phr (part hundred rubber) NR filled by 50 phr CB respectively. Compared with NR composites, SBR/NBR addition improved the hardness and density slightly. While tensile strength, modulus, abrasion resistance, and compression set decreased significantly. The volume, hardness, and physical properties were measured before and after 28 days of immersion in acidic, alkalis, and salty solutions. It was found that the higher loading SBR/NBR enhances chemical resistance. The hydrochloric and sulphuric acid immersion influenced the physical changes more vigorously. The thermal aging evaluation was observed by measuring the hardness and tensile strength at hot air circulation of 70°C for 24; 48 and 72 hours. The higher SBR/NBR loading could minimize the changes in hardness and tensile strength. To sum up, SBR/NBR addition improves the chemical and heat resistance on ternary blends.

Modification in durability of mango wood through reactive reinforcement of polyacrylonitrile

Reactive reinforcement of polyacrylonitrile (PAN) into mango wood (MW) has afforded a series of wood polymer composites (WPCs) with improved mechanical properties, resistance against solvents, chemicals and biodegradation. The process of reactive reinforcement of PAN into MW was conducted through treatment of leached MW panels with a composition of acrylonitrile (AN, 20–60 v/v) and 2,2-azobisisobutyronitrile (1 wt%) in dimethyl formamide over 12 h under ambient conditions followed by curing at 95 ± 1 °C over additional 6 h. This has afforded a series of WPCs with PAN loading in the range of 5.5 to 15.0. Scanning electron microscopy in combination with wood content data reveals the loading (wt%) of PAN into the matrix of MW. PAN loading of 8.85 wt% was found optimum towards enhancing the compressive, impact and static bending strength of WPCs. PAN loading has raised the resistance of WPCs in organic solvents, hot water and aqueous NaOH. WPC with PAN loading of 15 wt% has shown enhanced resistance against biodegradation in presence of a decay fungus Coriolous versicolor. This has been revealed through the controlled release of protein, reducing sugar contents and enzyme activities in presence of a decay fungus under incubation over 168 hr. The present investigation reveals a viable method of reinforcement of PAN into MW to achieve the WPCs with improved strength, stability in degrading chemicals, controlled biodegragation.

Influences of Acrylonitrile (AN) Content in Styrene–Acrylonitrile (SAN) Copolymer on the Mechanical Property, Thermo-deformation Resistance, and Morphology of PVC–ASA–DOP Blends

Abstract In this work, PVC–ASA–DOP blends were prepared by melt blending ASA (acrylate–styrene–acrylonitrile) graft copolymer, poly(vinyl chloride) (PVC) resin with dioctyl phthalate (DOP). The effects of AN content on the property of the blends were investigated. The results showed that the mechanical property depended on AN content in the SAN copolymer, and PVC was immiscible with the SAN copolymer over the entire AN composition range. Thermo-deformation resistance was dependent on Tg and the storage modulus. From SEM, it was found that the morphology was consistent with the property.

An Experimental Raman and Theoretical DFT Study on the Self-Association of Acrylonitrile

The liquid structure of acrylonitrile (propenenitrile) has been investigated using Raman spectroscopy and density functional theory (DFT) ab initio calculations with the 6-311++G** basis set. Two different and complementary experimental approaches were undertaken: FT-Raman spectra of 13 acrylonitrile solutions in carbon tetrachloride (concentration range=0.25-12.0 mol.L-1) were studied in detail including principal component analysis (PCA) of the CN stretching band. Furthermore, dispersive Raman spectra of neat acrylonitrile were obtained at eight different temperatures from 238 up to 343 K. The complex and asymmetric acrylonitrile Raman CN stretching band can be decomposed into two components attributed to monomeric and self-associated forms. Ab initio results fully support this assignment and suggest that the self-associated complex is a nonplanar trimer held together by dipole-dipole interactions. At ambient temperature, the composition of acrylonitrile can be expressed as a mixture of 25% monomers and 75% trimers. Close to the boiling point, trimers still represent 65% of the liquid composition. The corresponding enthalpy of association was estimated to be -22+/-2 kJ.mol-1.

Electrical conductivity of prelocalized graphite‐filled blend of polyvinyl chloride/styrene acrylonitrile composites in relationship to morphology and hardness

AbstractAt present there is a greater need to design conducting polymeric composites that suit particular application with little compromise on mechanical properties. This work deals with the study of electrical conductivity and mechanical strength of graphite‐filled blend of polyvinyl chloride/styrene acrylonitrile (PVC/SAN) composites. Samples were prepared by prelocalization of graphite onto the particles of PVC and SAN with subsequent compression molding. At a fixed volume ratio of 1:1 of PVC/SAN, percolation threshold of 0.0063 volume fraction of graphite has been observed. SAN has improved the D‐shore hardness of composites. Composites with more than 3 wt% graphite content have good conductivity and still preserve a reasonable mechanical strength. Conductivity patterns suggest higher affinity of graphite for PVC as compared to SAN. Scanning electron microscopy (SEM) micrographs indicate the widening of graphite layers with increasing graphite content. The electrical conductivity of composites has been explained in terms of percolation theory. The universal exponent t is found to be 3.09 for a best‐fit value of percolation threshold of 0.0057 volume fraction of graphite. There is good agreement between calculated and experimental values. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

An optical chemical sensor based on functional polymer films for controlling sulfur dioxide in the air of the working area: Acrylonitrile and alkyl methacrylate copolymers with brilliant green styrene sulfonate

The effects of the chemical and phase composition of acrylonitrile and alkyl methacrylate (Alkyl-MA) copolymers with styrene sulfonates (SS) of triphenylmethane dye cations on the gas permeability and sensing properties of their films were studied for developing an optical chemical sensor (OCS) for sulfur dioxide (SO2) on the basis of functional polymers. Of the three triphenylmethane dyes tested, namely, fuchsine, Crystal Violet, and Brilliant Green (BG), only the last dye was selected for molecular design. It was shown that the copolymer of Decyl-MA with SS—BG with the degree of modification DM = 0.10 is the best material among the studied ones from the viewpoints of sensitivity, response time, and time stability of sensor characteristics. The conditions for fabricating polymer films and the parameters of their functioning in OCSs for SO2 were optimized. The effect of annealing conditions on the sensitivity of spectra to SO2 was studied. Working temperature, working wavelength, and the conditions for the regeneration of the initial spectral parameters were optimized. Calibration characteristics of OCSs for the dynamic admittance of SO2—air mixtures were obtained. The calculated detection limit for SO2 in an air flow for a sensor with a sensing film fabricated of the decyl-MA—SS—BG copolymer with DM = 0.10 was 0.16 vol %, or 4160 mg/m3. This points to the necessity of searching for more sensitive sensing materials among other classes of functional polymers.

One-Step Formation of Morphologically Controlled Nanoparticles with Projection Coronas

Nanoparticles with projection coronas were prepared by the one-step dispersion terpolymerization of styrene, acrylonitrile, and poly(ethylene glycol) monomethacrylate in ethanol−water solution, and their morphologies were controlled. When the mole composition of acrylonitrile to the total monomers CAN was 0.49−0.66, electron microscopy showed that the nanoparticles were spherical and had a number of projections on the surface. A CAN of more than 0.66 yielded no nanospheres, and a CAN smaller than 0.49 yielded projection-free nanospheres. The morphology of the nanospheres could be controlled by changing the reaction conditions, and some conditions yielded a regular arrangement of uniform projections on the surface similar to that seen in some coronaviruses. X-ray and spectroscopic studies suggested that the projections might be formed as a result of the nonequilibrated swelling of acrylonitrile and poly(ethylene glycol) domains on the surface.

Impact strength in ABS–PPO blends compatibilized with styrene–acrylonitrile–glycidil methacrylate terpolymers

The impact strength of the acrylonitrile-co-butadiene-co-styrene terpolymer–poly(2,6-dimethyl-1,4-phenylene oxide (ABS–PPO) blends compatibilized with styrene–acrylonitrile modified with glycidil methacrylate (SAN–GMA) terpolymer can be significantly enhanced by the various processing conditions in reaction extrusion. Four different ABS terpolymers are used depending on the composition of acrylonitrile, styrene, and butadiene. The morphology of polybutadiene latex in ABS-1, ABS-3, and ABS-4 is an agglomerated type, while that of ABS-2 is a bimodal one. The three different methods in in situ compatibilizing extrusion are employed; the simple mixing of ABS and PPO, the simultaneous mixing of ABS and PPO, the reactive compatibilizer SAN–GMA, maleic anhydride (MA; designated A-series), and then the stepwise mixing of the mixtures of ABS–SAN–GMA in the MA-modified PPO (designated B-series). Although the ABS-4–PPO blend depicted the highest impact strength in the simple mixing, the ABS-3B–PPO blend showed the best impact strength in the stepwise mixing. The former behavior may be arisen from the high content of BR, whereas the latter may be due to the agglomerated rubber phase with SAN–GMA. The highest impact strength (47 kg·cm·cm−1) was observed in ABS-3B–PPO at 50/50 with an inclusion of 10 wt % GMA (2) and 1 wt % MA. Thus, the proposed reaction mechanism is an existence of the compatibility between ABS and SAN–GMA and the reactivity between the MA-modified PPO and SAN–GMA. Phase morphology of the ABS-2–PPO and ABS-3–PPO blends were compared, and more efficient dispersion of ABS was observed in the B-series than in the A-series. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 841–852, 1999

Impact strength in ABS-PPO blends compatibilized with styrene-acrylonitrile-glycidil methacrylate terpolymers

The impact strength of the acrylonitrile-co-butadiene-co-styrene terpolymer–poly(2,6-dimethyl-1,4-phenylene oxide (ABS–PPO) blends compatibilized with styrene–acrylonitrile modified with glycidil methacrylate (SAN–GMA) terpolymer can be significantly enhanced by the various processing conditions in reaction extrusion. Four different ABS terpolymers are used depending on the composition of acrylonitrile, styrene, and butadiene. The morphology of polybutadiene latex in ABS-1, ABS-3, and ABS-4 is an agglomerated type, while that of ABS-2 is a bimodal one. The three different methods in in situ compatibilizing extrusion are employed; the simple mixing of ABS and PPO, the simultaneous mixing of ABS and PPO, the reactive compatibilizer SAN–GMA, maleic anhydride (MA; designated A-series), and then the stepwise mixing of the mixtures of ABS–SAN–GMA in the MA-modified PPO (designated B-series). Although the ABS-4–PPO blend depicted the highest impact strength in the simple mixing, the ABS-3B–PPO blend showed the best impact strength in the stepwise mixing. The former behavior may be arisen from the high content of BR, whereas the latter may be due to the agglomerated rubber phase with SAN–GMA. The highest impact strength (47 kg·cm·cm−1) was observed in ABS-3B–PPO at 50/50 with an inclusion of 10 wt % GMA (2) and 1 wt % MA. Thus, the proposed reaction mechanism is an existence of the compatibility between ABS and SAN–GMA and the reactivity between the MA-modified PPO and SAN–GMA. Phase morphology of the ABS-2–PPO and ABS-3–PPO blends were compared, and more efficient dispersion of ABS was observed in the B-series than in the A-series. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 841–852, 1999

Effect of methyl acrylate composition on the microstructure changes of high molecular weight polyacrylonitrile for heat treatment

The acrylate comonomer in polyacrylonitrile (PAN) precursor markedly influences the microstructure of PAN fiber and its resulting carbon fiber. In this study, the change occurring during the heat treatment of PAN copolymers (acrylonitrile-co-methyl acrylate) in the presence of air up to 260°C has been examined using both physical and chemical techniques. Considering the effect of the methyl acrylate content of PAN copolymers on the cyclization mechanism and fine structural changes in polymer chains under various heat treatment conditions, the composition of acrylonitrile and methyl acrylate = 98 : 2 to 97 : 3 mol % was suitable for the precursor preparation because the cyclization mechanism and fine structural changes in the boundary of this composition of copolymers were significantly different. With increasing MA content, the exothermic onset and peak in the thermogram was found to shift toward higher temperatures, and the aromaticity index decreased. This evidence indicates that MA was believed not to activate at all but to interfere with the cyclization. Additionally, by means of 13C nuclear magnetic resonance (13C-NMR) analysis, the tacticities of copolymers were nearly same, regardless of the copolymer composition, and the cyclization occurred nonstereospecifically during the initial heat treatment at 240°C for 1 h. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 2205–2213, 1998

Effect of Acrylonitrile Composition in NBR on Enhanced Anion Doping‐Undoping Process of NBR‐Guided‐Grown‐Polypyrrole Film Electrode

The anion doping‐undoping process of NBR (nitrile butadiene rubber)‐guided‐grown‐polypyrrole (PPy/NBR) film electrode was investigated by varying the precoated NBR film thickness and the acrylonitrile content in the NBR host polymer. The electrode kinetics and the morphology orientation of the PPy/NBR film were found to depend greatly on the nature of the precoated NBR film. Compared to a normally polymerized PPy film, a PPy/NBR film formed particularly with anion showed an enhanced switching reversibility and an acceleration of the dopant movement within the polymer layer. Impedance analysis revealed that the PPy/NBR films show a clear change in their overall electrode process, from a charge transfer limiting process to a diffusion limiting process according to an increase in the precoated NBR thickness and also to a decrease in the acrylonitrile content of the NBR film. The perpendicularly formed morphology is easily formed when using NBR with less acrylonitrile. The rechargeable lithium battery with a PPy/NBR cathode shows a better charging‐discharging performance than a PPy/NBR cathode formed with a lower AN content NBR.

Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA2)

AbstractThis article deals with studies of the dilute solution properties of methyl methacrylate‐acrylonitrile (MMA‐AN) copolymer of 0.415 mole fraction (mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2‐butanone (MEK), dimethyl formamide (DMF), and γ‐butyrolactone (γ‐BL). The Mark‐Houwink exponent a in all four solvents at all temperatures is larger than the corresponding values of the parent homopolymers. The solvent power is in the order of DMF < γ–BL < MEK < MeCN; [η] decreases with an increase in temperature, which is behavior characteristic of polymers in good solvent. The unperturbed dimensions (K0) values, obtained by the Stockmayer–Fixman method, are lower than those for the parent homopolymers and depend on solvent as well as temperature. The solute—solvent interaction parameter X1 values are close to 0.5; X1 is independent of temperature. The excess interaction parameter XABvalues are negative. The results for this copolymer system in regard to low second virial coefficient A2, large X1, and high a values suggest that the large extension of these copolymer chains is due to the unusual short‐range interactions.

Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA1)

This paper deals with studies on the dilute solution properties of methyl methacrylate—acrylonitrile copolymer of 0.289 mole fraction ( mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2-butanone (MEK), dimethylformamide (DMF) and γ-butyrolactone (γ-BL). The solvent power is found to be in the order of MEK < MeCN < DMF < γ-BL at 30°C. Herein, probably for the first time, the steric factor for the copolymer is found to be lower than that for the parent homopolymers and the excess interaction parameter, χ AB is found to be negative. This probably suggests that the units are compatible to each other.

Elongational and Shear Viscosities of a Bead-Filled Thermoplastic

Elongational and shear viscosities of bead-filled styrene acrylonitrile composites were measured in the rubbery flow region at very low strain rates. Composites contained 9–37% spherical glass beads by volume. Within experimental error, elongational viscosity was found to be constant and equal to three times shear viscosity at very low strain rates for the composites containing less than 20 vol % glass beads. The experimental data were used to evaluate a number of the classical theories for the viscosity of suspensions. In general, the theories were more appropriate for the elongational than for the shear data. Both elongational and shear viscosities were discovered to have the same dependence on the filler concentration up to 20 vol % glass beads. Dewetting is very noticeable in high strain tensile testing for all nonzero filler concentrations. In the data presented here, simultaneous measurements of longitudinal extension and lateral contraction established that the samples did not dewet during the viscosity measurements.

Composites formed by interstitial polymerization of vinyl monomers in polyurethane elastomers: 4. Preparation, properties and structure of acrylonitrile and styrene based composites

The preparation of composites by interstitial polymerization of acrylonitrile in a polyurethane and also of styrene in a polyurethane are described. The styrene composites are more difficult to prepare but the acrylonitrile composites are similar in ease of preparation, appearance and properties to that of the MMA composites described in Parts 1 and 2. The polymerization conditions, morphology, relaxation properties and impact strength for a series of composites of each kind are reported and compared with the corresponding MMA composites.