Mechanical and thermal properties of (acrylonitrile‐styrene‐acrylic)/(α‐methylstyrene‐acrylonitrile) binary blends

In this work, (acrylonitrile‐styrene‐acrylic)/(α‐methylstyrene‐acrylonitrile) copolymer (ASA/α‐MSAN) binary alloy was prepared with different composition ratios via melt blending. This work mainly focused on improving the heat resistance of ASA. According to the results of dynamic mechanical thermal analysis, the binary blends exhibited three glass transition temperatures (T_gs) and the shift of the T_gs indicated the partial miscibility of binary blends. This partial miscibility maintained the high T_g of α‐MSAN, which led to the outstanding heat resistance of binary blends. Furthermore, heat distortion temperature also showed that the heat resistance of binary blends was significantly enhanced with the addition of α‐MSAN. However, the introduction of this highly rigid polymer also brought with it the sharp decrease of the impact strength and elongation at break, which is reflected in the morphologies of the blend system obtained via scanning electron microscopy. In addition, the incorporation of α‐MSAN increased the tensile strength, flexural strength, and modulus. There were no new groups observed from Fourier‐transform infrared spectra, which means no strong specific intermolecular interactions existed between ASA and α‐MSAN. Moreover, the processibility of the blend system was obviously improved from the results of melt flow rate. J. VINYL ADDIT. TECHNOL., 22:156–162, 2016. © 2014 Society of Plastics Engineers     

High‐impact toughness poly(vinyl chloride)/(α‐methylstyrene)‐acrylonitrile‐butadiene‐styrene copolymer/acrylic resin blends: Thermal properties and toughening mechanism

High impact toughness poly(vinyl chloride) (PVC)/(α‐methylstyrene)‐acrylonitrile‐butadiene‐styrene copolymer (70/30)/acrylic resin (ACR) blends were prepared. Incorporation of ACR did not play a negative role in thermal properties. The glass transition temperature, heat distortion temperature, and thermal stability remained constant as ACR content increased. With the addition of 10 phr (parts by weight per hundred parts of resin) of ACR, the impact strength increased by 20.0 times and 7.2 times compared with that of pure PVC and that of PVC/(α‐methylstyrene)‐acrylonitrile‐butadiene‐styrene copolymer (70/30) blends, respectively. However, tensile strength and flexural properties decreased. The morphology changed from domain distortions to crazing with fibrillar plastic deformation as ACR content increased. The toughening mechanism varied from “shear yielding” to “craze with shear yielding,” which depended on the content of ACR. This study presents the finding that addition of ACR drastically improved impact toughness without sacrificing any heat resistance, and the enhanced impact strength could be at the same level of supertough nylon. J. VINYL ADDIT. TECHNOL., 21:205–214, 2015. © 2014 Society of Plastics Engineers     

Room temperature and low temperature toughness improvement in SAN/ASA blends by blending with CPE,HNBR, and BR

Styrene‐acrylonitrile copolymer (SAN)/acrylonitrile‐styrene‐acrylate terpolymer (ASA) blends (75/25, wt/wt) was toughened by blending with impact modifiers including chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), and butadiene rubber (BR) and the impact property was tested at four temperatures (–30, ?15, 0, and 25 °C). The combination of CPE and HNBR was imported to toughen the SAN/ASA blends, indicating that CPE and HNBR had similar toughening effect at room temperature but HNBR exhibited a better performance at low temperature. When a little HNBR was substituted by BR, the impact strength improved dramatically with the total content of impact modifiers keeping at 30 phr. After 15 phr CPE, 10 phr HNBR and 5 phr BR were employed into blends together, the impact strength reached to a peak of 14 kJ/m² at ?30 °C while the impact strength of the blends individually toughened by 30 phr CPE or 30 phr HNBR was 5 or 12 kJ/m², respectively. The toughening mechanism showed that the low glass‐transition temperature (–108 °C) of BR and the compatibilization between BR and matrix accounted for the improvement of toughness. Simultaneously, scanning electron microscopy, dynamic mechanical analysis, flexural and tensile properties, heat distortion temperature, and Fourier transform infrared spectroscopy were measured. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45364.     

Mechanical and thermal properties of poly(vinyl chloride)/α‐methyl‐styrene‐acrylonitrile blends prepared by melt extrusion

In this article, we have examined the physical and mechanical properties of poly(vinyl chloride) (PVC)/α‐methyl‐styrene‐acrylonitrile (αMSAN; 31 wt % AN concentrations) blends with different blend ratios. And, we also examined the effect of the molecular weights of PVC on the miscibility and material properties of the blends prepared by melt extrusion blending. Our results showed that the PVC/αMSAN blends have good processing properties and good miscibility over all blend ratios because of the strong interaction between PVC and αMSAN. And, the blends showed enhanced mechanical and thermal properties. In addition, high molecular weight PVC showed reasonable processability when melt blended with αMSAN, which resulted in enhanced mechanical and physical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mechanical properties and deformation behaviors of acrylonitrile‐butadiene‐styrene under Izod impact test and uniaxial tension at various strain rates

Two polybutadiene‐graft‐acrylonitrile‐styrene copolymer (PBD‐g‐SAN) impact modifiers with different rubber particle size were synthesized by seeded emulsion polymerization. Acrylonitrile‐butadiene‐styrene (ABS) blends with a constant rubber concentration of 15 wt% were prepared by blending those impact modifiers and SAN resin. The major focus was the mechanical properties and deformation mechanisms of ABS blends under Izod impact test and uniaxial tension at various strain rates from 2.564 × 10^?4 S^?1 upto 1.282 × 10^?1 S^?1. By the combination of transmission electron microscope and scanning electron microscope, it was concluded that crazes and cavitation coexisted in ABS blends. The deformation mechanisms of ABS blend containing large rubber particles was rubber particles cavitation and shear yielding in the matrix including crazes, and they do not change with the strain rate. Different from ABS blend with large rubber particles, deformation mechanism of ABS with small rubber particles under tensile condition was only involved in shear yielding in the matrix and no crazes were formed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Syntheses and adsorption properties for Hg2+ of chelating resin of crosslinked polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole

A novel chelating resin with functional group containing S and N atoms was prepared using chloromethylated polystyrene and 2,5‐dimercapto‐1,3,4‐thiodiazole (also called bismuththiol I, BMT) as materials. Its structure was characterized by infrared spectra and elementary analysis. The results showed that the content of the functional group was 2.07 mmol BMT g^?1 resin, 47% of which were in the form of monosubstitution (PS‐BMT‐1) and 53% in the form of double substitution (PS‐BMT‐2). The adsorption for mercury ion was investigated. The adsorption dynamics showed that the adsorption was controlled by liquid film diffusion. Increasing the temperature was beneficial to adsorption. The Langmuir model was much better than the Freundlich model to describe the isothermal process. The adsorption activation energy (E_a), ΔG, ΔH, and ΔS values calculated were 18.56 kJ·mol^?1, ‐5.99 kJ·mol^?1, 16.38 kJ·mol^?1, and 37.36, J·mol^?1·K^?1, respectively. The chelating resin could be easily regenerated by 2% thiourea in 0.1 mol·L^?1 HCl with higher effectiveness. Five adsorption–desorption cycles demonstrated that this resin was suitable for repeated use without considerable change in adsorption capacity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1646–1652, 2004     

Toughening modification of poly(vinyl chloride)/ α‐methylstyrene‐acrylonitrile‐butadiene‐styrene copolymer blends via adding chlorinated polyethylene

In this study, poly (vinyl chloride) (PVC)/α‐methylstyrene‐acrylonitrile‐butadiene‐styrene copolymer (AMS‐ABS) (70/30)/chlorinated polyethylene (CPE) ternary blends was prepared. With the addition of CPE, it did not exert a negative influence in both the glass transition temperature and heat distortion temperature. Thermogravimetric analysis showed that addition of CPE did not play a negative role in the thermal stability. With regard to mechanical properties, high toughness was observed combined with the decrease in tensile strength and flexural strength. With the addition of 15 phr CPE, the impact strength increased by about 21.0 times and 8.5 times in comparison with pure PVC and PVC/AMS‐ABS (70/30) blends, respectively. The morphology correlated well with the impact strength. It was also suggested from the morphology that shear yielding was the major toughening mechanisms for the ternary blends. And there existed a change in the fibril structures that are observed in scanning electron microphotographs. Our present study shows that combination of AMS‐ABS and CPE improves the toughness without sacrificing the heat resistance, and the value of notched impact strength can be enhanced to the same level of super‐tough nylon. POLYM. ENG. SCI., 54:378–385, 2014. © 2013 Society of Plastics Engineers     

Performance evaluation of chlorinated polyethylene compatibilized‐industrial waste‐filled acrylonitrile butadiene rubber/low‐density polyethylene blends

Chlorinated polyethylene as a compatibilizer at various levels was mixed in a Brabender^® internal mixer with different ratios of (acrylonitrile butadiene rubber)/(low‐density polyethylene) that contained industrial marble waste. Vulcanized articles were fabricated. The properties were investigated by cure characteristics, and mechanical and swelling parameters. The natural weathering impact on these properties was also evaluated within the span of 6 to 12 months. Notable improvements were recorded in the cure, and mechanical and swelling behaviors of uncompatibilized and chlorinated polyethylene compatibilized marble waste‐‐filled (acrylonitrile butadiene rubber)/(low‐density polyethylene) blends. Considerable losses in mechanical properties were found for all specimens because of environmental oxidation. J. VINYL ADDIT. TECHNOL., 22:460–469, 2016. © 2015 Society of Plastics Engineers     

Modeling the PAAc‐AN‐TV surface using 134Cs and 152+154Eu sorption

A novel composite, composed of poly (acrylic acid (AAc), acrylonitrile, and titanium vanadate, was prepared by induced gamma irradiation route at 20 kGy to be used as a hybrid organic‐inorganic sorbent. 5–200 μm particle diameters of the composite were obtained. An average particle size of 75 μm of crystalline (17‐20) composite was used; it was thermally stable to 486°C. The distribution coefficients of Cs⁺ and Eu³⁺ were studied as a function of pH; 2350 mL·g^?1 and 645 mL·g^?1 were obtained in case of ^152+154Eu and ¹³⁴Cs at pH 6. 1.55 mmol·g^?1 and 1.85 mmol·g^?1 maximum loadings were accommodated for the same ions at the same pH. Different models were used to scan the surface of the exchanger, so that the topography of the surface was studied as a function of surface active site types, concentrations, and heterogeneity. Langmuir, Freundlich and D‐R models were used. Also, different kinetic models, as Lagergren pseudo first‐order, pseudo second‐order and Morris‐Weber intraparticle diffusion models were applied to study the possible mechanism of the sorption process; pseudo first‐order was exempted to investigate the mechanism. They proved that chemisorption and ion exchange mechanism with controlled diffusion are predominant, with their characteristic mean energies (8.731 kJ·mol^?1 and 9.310 kJ·mol^?1 for Cs⁺ and Eu³⁺, respectively). Double Shell Model was finally adopted to explain the suggested mechanism. Negative values of ΔG°, ?2.15 kJ·mol^?1 to ?7.92 kJ·mol^?1 in case of Cs⁺ and ?3.35 kJ·mol^?1 to ?9.67 kJ·mol^?1 in case of Eu³⁺adsorption at different temperatures, indicate the spontaneous nature of the reactions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Design and preparation of cross‐linked α‐methylstyrene‐acrylonitrile copolymer nano‐particles for elastomer reinforcement

Crosslinked α‐methylstyrene and acrylonitrile (MStAN) copolymer particles in a latex form were synthesized by free radical emulsion polymerization. The particles took a spherical shape with an average size of 53.1 nm in a narrow distribution. When filled into styrene‐butadiene rubber (SBR), nitrile‐butadiene rubber (NBR), and natural rubber (NR), the MStAN nano‐particles exhibited excellent reinforcing capabilities and the best in NBR. By the employment of heat treatment, mechanical properties of the MStAN‐filled SBR composites had got remarkable further improvements. But mechanical properties, together with the morphology, of the MStAN‐filled NBR composites, varied little after heat treatment, which, however, divulged the naturally good compatibility between the MStAN particles and the NBR matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improvement in the heat resistance of poly(vinyl chloride) profile with styrenic polymers

The styrenic polymers poly(α‐methylstyrene‐acrylonitrile) (α‐MSAN) and poly(acrylonitrile‐butadiene‐styrene) (ABS) and (three types) were used to improve the heat resistance of poly(vinyl chloride) (PVC). The glass transition temperature (T_g) and miscibility were analyzed by dynamic mechanical thermal analysis (DMTA). Effects of composition on heat distortion temperature (HDT) were investigated with the different styrenic polymers. Other physical properties such as mechanical properties and melt flow rate (MFR) were also determined. Morphology was observed by scanning electron microscopy (SEM) in order to support the mechanical property results. The PVC was miscible with α‐MSAN but partially miscible with the ABS series, and α‐MSAN was much more effective in enhancing the T_g and HDT of rigid PVC than the ABS series as for mechanical properties, the addition of α‐MSAN could improve the tensile strength, bending strength, and bending modulus but decrease the impact strength of the materials compared with the addition of the ABS series. Improvement in processability was observed in the MFR results with the addition of the styrenic polymers. On the basis of all the properties, the formulation with an α‐MSAN content of 30 phr (parts per hundred parts of resin) was superior for heat‐resistant PVC profile. The HDT of PVC could be increased from 76.9°C to 85.4°C (measured under the maximum bending stress of 0.45 MPa) and combined with good mechanical properties and processability by the addition of 30 phr of α‐MSAN. Also, a heat‐resistant PVC profile was successfully fabricated. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Thermoplastic elastomeric blend of nitrile rubber and poly(styrene‐co‐acrylonitrile). II. Replacement of nitrile rubber by its vulcanizate powder

A model waste nitrile rubber powder (w‐NBR) was prepared by ambient grinding of aged NBR vulcanizate based on an oil seal formulation. The w‐NBR was characterized by scanning electron microscopic and optical microscopic techniques. Virgin nitrile rubber in a thermoplastic elastomeric 70:30 nitrile rubber/poly(styrene‐co‐acrylonitrile) (SAN) blend was replaced by w‐NBR, and the mechanical properties and swelling index were determined. The virgin NBR in the blend was replaced by the rubber present in w‐NBR (r‐w‐NBR) and the optimum mechanical properties were achieved at 45% replacement where the blend was still reprocessable. Transmission electron microscopic and atomic force microscopic studies reveal that w‐NBR particles coated with NBR are dispersed in a continuous SAN matrix. It was observed that migration of unreacted curatives from w‐NBR to virgin NBR is not significant and incorporation of curatives is necessary for attainment of optimum level of mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2348–2357, 2003     

Miscibility of poly(α-methyl siyrene-co-acrylonitrile) with polyacrylates and polymethacrylates

A copolymer formed from 30 percent acrylonitrile and 70 percent α methyl styrene by weight, or αMSAN, has been examined for miscibility in blends with various polyacrylates and polymethacrylates. None of the polyacrylates or poly(vinyl acetate) were miscible with α-MSAN at room temperature or above. The methyl and ethyl esters of the polymethacrylate series (PMMA, PEMA) proved to be miscible with α MSAN, but none of the higher homologues were miscible under these conditions. Blends of both PMMA and PEMA with α MSAN exhibited lower critical solution temperatures. The observed cloud points decreased as PMMA molecular weight increased up to 10⁵ where kinetic effects caused an apparent reversal of this trend. Atactic PMMA interacts more strongly with αMSAN than does either isotactic PMMA or atactic PEMA. These structural effects are compared with similar trends found in other systems.     

Morphology and mechanical properties of ABS blends prepared from emulsion‐polymerized PB‐g‐SAN impact modifier with AIBN as initiator

A series of PB‐g‐SAN impact modifiers (polybutadiene particles grafted by styrene and acrylonitrile) are synthesized by seed emulsion copolymerization initiated by oil‐soluble initiator, azobisiobutyronitrile (AIBN). The ABS blends are obtained by mixing SAN resin with PB‐g‐SAN impact modifiers. The mechanical behavior and the phase morphology of ABS blends are investigated. The graft degree (GD) and grafting efficiency (GE) are investigated, and the high GD shows that AIBN has a fine initiating ability in emulsion grafting of PB‐g‐SAN impact modifiers. The morphology of the rubber particles is observed by the transmission electron microscopy (TEM). The TEM photograph shows that the PB‐g‐SAN impact modifier initiated by AIBN is more likely to form subinclusion inside the rubber particles. The dynamic mechanical analysis on ABS blends shows that the subinclusion inside the rubber phase strongly influences the T_g, maximum tan δ, and the storage modulus of the rubber phase. The mechanical test indicates that the ABS blends, which have the small and uniform subinclusions dispersed in the rubber particles, have the maximum impact strength. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Toughening effect of PNBR on ASA/SAN binary blends

In this work, (acrylonitrile‐styrene‐acrylic terpolymer)/(styrene‐acrylonitrile copolymer)/(powder nitrile butadiene rubber) ternary blends with different compositions were prepared by melt blending. Differential scanning calorimetry, dynamic mechanical analysis, and Fourier‐transform infrared spectra were used to analyze the glass transition behavior and interactions among components of the blends, while scanning electron microscopy was used to observe the microstructure. Furthermore, mechanical properties, heat resistance, and melt flow rate of the blends were tested. The results showed that addition of powder nitrile butadiene rubber can enhance toughness of the blends on a large scale, and the blend system seems to be miscible according scanning electron microscopy images. J. VINYL ADDIT. TECHNOL., 20:268–274, 2014. © 2014 Society of Plastics Engineers     

Influence of core–shell particles structure on the morphology and brittle‐ductile transition of PBT/ABS‐g‐GMA blends

The performance of glycidyl methacrylate (GMA) functionalized acrylonitrile‐butadiene‐styrene core–shell impact modifiers (R‐ABS) with varied GMA content, crosslinking degree of rubber phase, core–shell ratio, and initiator type in toughening of poly(butylene terephthalate) (PBT) was investigated. Results show that 1 wt% GMA is sufficient to induce a pronounced improvement of the impact strength of PBT and too much GMA induces the crosslinking of R‐ABS. Divinylbenzene improves the crosslinking degree of polybutadiene and decreases its cavitation ability. The brittle‐ductile transition shifts to higher R‐ABS content. When the core–shell ratio of R‐ABS is beyond 70/30, compatibilization reaction is not sufficient to retard the agglomeration of core–shell particles. R‐ABS particles with the core–shell ratio between 50/50 and 60/40 are suitable. Initiator type can influence the internal structure of R‐ABS. For R‐ABS prepared with azobisisobutyronitrile (AIBN) as initiator, big subinclusion structure decreases its toughening ability. R‐ABS prepared with redox initiator shows better toughening behavior. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Effects of the polybutadiene/poly(styrene‐co‐acrylonitrile) ratio in a polybutadiene‐g‐poly(styrene‐co‐acrylonitrile) impact modifier on the morphology and mechanical behavior of acrylonitrile–butadiene–styrene blends

Polybutadiene‐g‐poly(styrene‐co‐acrylonitrile) (PB‐g‐SAN) impact modifiers with different polybutadiene (PB)/poly(styrene‐co‐acrylonitrile) (SAN) ratios ranging from 20.5/79.5 to 82.7/17.3 were synthesized by seeded emulsion polymerization. Acrylonitrile–butadiene–styrene (ABS) blends with a constant rubber concentration of 15 wt % were prepared by the blending of these PB‐g‐SAN copolymers and SAN resin. The influence of the PB/SAN ratio in the PB‐g‐SAN impact modifier on the mechanical behavior and phase morphology of ABS blends was investigated. The mechanical tests showed that the impact strength and yield strength of the ABS blends had their maximum values as the PB/SAN ratio in the PB‐g‐SAN copolymer increased. A dynamic mechanical analysis of the ABS blends showed that the glass‐transition temperature of the rubbery phase shifted to a lower temperature, the maximum loss peak height of the rubbery phase increased and then decreased, and the storage modulus of the ABS blends increased with an increase in the PB/SAN ratio in the PB‐g‐SAN impact modifier. The morphological results of the ABS blends showed that the dispersion of rubber particle in the matrix and its internal structure were influenced by the PB/SAN ratio in the PB‐g‐SAN impact modifiers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2165–2171, 2005     

Toughness,dynamic mechanical property,and morphology of polyvinylchloride/acrylonitrile‐styrene‐butyl acrylate blends

Acrylonitrile‐styrene‐butyl acrylate (ASA) graft copolymers with different acrylonitrile (AN) contents, the core‐shell ratio, and tert‐dodecyl mercaptan (TDDM) amounts were synthesized by seed emulsion polymerization. Polyvinylchloride (PVC)/ASA blends were prepared by melt blending ASA graft copolymers with PVC resin. Then the toughness, dynamic mechanical property, and morphology of the PVC/ASA blends were investigated. The results indicated that the impact strength of the PVC/ASA blends increased and then decreased with the increase of the AN content in poly(styrene‐co‐acrylonitrile (SAN) copolymer, and increased with the increase of the core‐shell ratio of ASA. It was shown that brittle‐ductile transition of PVC/ASA blends was dependent on poly(butyl acrylate) (PBA) rubber content in blends and independent of AN content in SAN copolymer. The introduction of TDDM made the toughness of PVC/ASA blends poor. Dynamic mechanical analysis (DMA) curves exhibited that PVC and SAN copolymers were immiscible over the entire AN composition range. From scanning electron microscopy (SEM), it was found that the dispersion of ASA in PVC/ASA blends was dependent on the AN content in SAN copolymer and TDDM amounts. J. VINYL ADDIT. TECHNOL., 22:43–50, 2016. © 2014 Society of Plastics Engineers     

Modification of butadiene–acrylonitrile and styrene–acrylonitrile copolymerizations in emulsion systems

Modification of acrylonitrile in copolymerizations with butadiene and with styrene in hot and cold emulsion recipes has been studied. Series of primary, secondary, and tertiary mercaptans in addition to several miscellaneous modifiers were tested. Kinetically the rate data for the monomer pairs containing acrylonitrile better fit first-order plots than the curves obtained for an ideal emulsion polymerization. In this study all modifier depletions in nitrile systems were plotted as log mercaptan versus log conversion and the slope of the curve was taken as the transfer constant. Normal mercaptans were inefficient modifiers in nitrile systems as determined in polymerization and depletion experiments. Secondary mercaptans, 2-nonyl, 2-decyl, and mixtures in this molecular weight range, were promising modifiers for low temperature (5°C.) nitrile systems. 2-Nonyl mercaptan gave enhanced modification by incremental addition of the modifier indicating this procedure could be used to advantage in preparing nitrile rubbers. The series of tertiary mercaptans from C₁₃ to C₇ showed an improvement in modification of low temperature nitrile systems as the molecular weight decreased. A plot of the data on a molar basis shows that the optimum modifier falls in the C₉–C₈ range. The optimum transfer constant for the most efficient modification of 70/30 and of 80/20 butadiene–acrylonitrile polymerizations at 5°C. terminated at 60% conversion is 2. Depletion data show that the transfer constant for a mercaptan decreases as the nitrile content in mixtures with butadiene increases. The properties of the vulcanizates of the 70/30 and 80/20 butadiene–acrylonitrile polymers prepared in the presence of low molecular weight mercaptans were equivalent to or better than those of the controls. These data show that nitrile polymers could be modified with a lower molecule weight mercaptan with no loss of properties but with a considerable saving in amount of modifier. Mercaptans are essential for the initiation of butadiene–acrylonitrile in the presence of persulfate at 50°C. For the hot nitrile rubber preparations, the series of mercaptan from t-C₁₀ to t-C₇ are efficient modifiers. However, the heptyl and octyl mercaptans are retarders, and the t-C₉ and t-C₁₀ are the preferred modifiers for efficiency and unretarded polymerization. The modification with a series of mercaptans ranging from t-C_13.2 to t-C₈ of 75/25 styreneacrylonitrile at 50°C. in presence of persulfate–bisulfite showed a consistent behavior. The transfer constant decreased in a regular manner as the molecular weight of the mercaptan increased, and for the series of tertiary modifiers the t-C₁₀ mercaptan was the most efficient as judged by a melt flow test.     

Synthesis and characterization of homo‐ and copolymers of 3‐(2‐cyano ethoxy)methyl‐ and 3‐[methoxy(triethylenoxy)]methyl‐3′‐methyl‐oxetane

Two oxetane‐derived monomers 3‐(2‐cyanoethoxy)methyl‐ and 3‐(methoxy(triethylenoxy)) methyl‐3′‐methyloxetane were prepared from the reaction of 3‐methyl‐3′‐hydroxymethyloxetane with acrylonitrile and triethylene glycol monomethyl ether, respectively. Their homo‐ and copolyethers were synthesized with BF₃· Et₂O/1,4‐butanediol and trifluoromethane sulfonic acid as initiator through cationic ring‐opening polymerization. The structure of the polymers was characterized by FTIR and¹H NMR. The ratio of two repeating units incorporated into the copolymers is well consistent with the feed ratio. Regarding glass transition temperature (T_g), the DSC data imply that the resulting copolymers have a lower T_g than pure poly(ethylene oxide). Moreover, the TGA measurements reveal that they possess in general a high heat decomposition temperature. The ion conductivity of a sample (P‐AN 20) is 1.07 × 10^?5 S cm^?1 at room temperature and 2.79 × 10^?4 S cm^?1 at 80 °C, thus presenting the potential to meet the practical requirement of lithium ion batteries for polymer electrolytes. Copyright © 2005 Society of Chemical Industry