Characterization of polyacrylonitrile,poly(acrylonitrile‐co‐vinyl acetate), and poly(acrylonitrile‐co‐itaconic acid) based activated carbon nanofibers

In this study, three different acrylonitrile (AN)‐based polymers, including polyacrylonitrile (PAN), poly(acrylonitrile‐co‐vinyl acetate) [P(AN‐co‐VAc)], and poly(acrylonitrile‐co‐itaconic acid) [P(AN‐co‐IA)], were used as precursors to synthesize activated carbon nanofibers (ACNFs). An electrospinning method was used to produce nanofibers. Oxidative stabilization, carbonization, and finally, activation through a specific heating regimen were applied to the electrospun fibers to produce ACNFs. Stabilization, carbonization, and activation were carried out at 230, 600, and 750 °C, respectively. Scanning electron microscopy, thermogravimetric analysis (TGA), and porosimetry were used to characterize the fibers in each step. According to the fiber diameter variation measurements, the pore extension procedure overcame the shrinkage of the fibers with copolymer precursors. However, the shrinkage process dominated the scene for the PAN homopolymer, and this led to an increase in the fiber diameter. The 328 m²/g Brunauer–Emmett–Teller surface area for ACNFs with PAN precursor were augmented to 614 and 564 m²/g for P(AN‐co‐VAc) and P(AN‐co‐IA), respectively. The TGA results show that the P(AN‐co‐IA)‐based ACNFs exhibited a higher thermal durability in comparison to the fibers of PAN and P(AN‐co‐VAc). The application of these copolymers instead of AN homopolymer enhanced the thermal stability and increased the surface area of the ACNFs even in low‐temperature carbonization and activation processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44381.     

Effect of different anchor groups on adsorption behavior and effectiveness of poly(N,N‐dimethylacrylamide‐co‐Ca 2‐acrylamido‐2‐methylpropanesulfonate) as cement fluid loss additive in presence of acetone–formaldehyde–sulfite dispersant

The impact of various anchor groups on adsorption behavior of AMPS® copolymers was studied. The anchor groups differ in anionic charge density. Copolymer adsorption and water retention of oil well cement slurries achieved from CaAMPS®‐co‐NNDMA in the presence of an acetone–formaldehyde–sulfite (AFS) dispersant were improved by incorporation of minor amounts (～ 1% by weight of polymer) of acrylic acid (CaAMPS®‐co‐NNDMA‐co‐AA), maleic acid anhydride (CaAMPS®‐co‐NNDMA‐co‐MAA), or vinyl phosphonic acid (CaAMPS®‐co‐NNDMA‐co‐VPA), respectively. Performance of these terpolymers was studied by measuring static filtration properties of oil well cement slurries at 27°C and 70 bar pressure. All fluid loss additives possess comparable molar masses and show the same adsorption behavior and effectiveness when no other admixture is present. In the presence of AFS dispersant, however, adsorption of CaAMPS®‐co‐NNDMA and hence fluid loss control is dramatically reduced, whereas effectiveness of CaAMPS®‐co‐NNDMA‐co‐AA is less influenced because of acrylic acid incorporated as additional anchor group. Even more, CaAMPS®‐co‐NNDMA‐co‐MAA combined with AFS allows simultaneous adsorption of both polymers and thus produces good fluid loss control. CaAMPS®‐co‐NNDMA‐co‐VPA no longer allows adsorption of AFS dispersant. This was also confirmed by rheological measurements. The results show that, in a binary admixture system, adsorption of the anionic polymer with anchor groups possessing higher charge density is preferred. Surface affinity of the anchor groups studied increase in the order ? SO → ? COO^? → vic‐(? COO^?)₂→ ? PO. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and elastomer behavior of a novel polymer electrolyte of acrylic ester–salt copolymer

This paper studied the synthesis of a novel elastomeric copolymer electrolyte in an aqueous phase. The monomer, sodium allyl sulfonate (SAS), was dissolved in continuous aqueous phase and the second monomer, methyl acrylate (MA), was supplied from MA micelles as dispersed phase. The copolymerization of the two monomers took place in continuous aqueous phase. Confirmed by FTIR and ¹H‐NMR, a binary copolymer electrolyte of MA and SAS, poly(MA‐co‐SAS), was obtained. The glass transition temperature of the copolymer was indicated as 20.4°C by DSC thermogram, thus, it behaves an elastomer in normal ambient temperature. The mechanical properties of the composite films consisting of both poly(MA‐co‐SAS) and Cu²⁺ ions or reduced copper were affected by the content of ions and reduced copper. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2796–2802, 2006     

Preparation of bi‐continuous poly(acrylonitrile‐co‐methyl acrylate) microporous membranes by a thermally induced phase separation method

Poly(acrylonitrile‐co‐methyl acrylate) [P(AN‐MA)] flat microfiltration membranes were successfully prepared via the thermally induced phase separation (TIPS) method, by using low polar caprolactam (CPL) and methoxypolyethylene glycol 550 (MPEG 550) as the mixed diluent. In this work, P(AN‐MA) membranes exhibit bi‐continuous networks, porous surfaces, high porosity, and big pore size, when membrane fabricated from a high MPEG 550 content, low P(AN‐MA) concentration, and small cooling rate, it can be dry state preservation and do not need to be impregnated by any solvent. When the ternary system was composed of 15 wt % P(AN‐MA), 12.5 wt % CPL, and 87.5 wt % MPEG 550, formed at 25 °C air bath, membrane has the highest water flux of 4420 L m^?2 h^?1. The obtained P(AN‐AN) membrane displays a high carbonic black ink rejection ranging from 83.7 to 98.5 wt %. Moreover, P(AN‐MA) polymer not only retains the advantages of PAN but also reduces the polar component from 16.2 to 10.77 MPa^0.5. It can be used membrane matrix to obtain pore structure and excellent mechanical property membrane via TIPS. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46173.     

Synthesis and characterization of poly(hydroxamic acid)–poly(amidoxime) chelating ligands from polymer‐grafted acacia cellulose

Graft copolymerization of methyl acrylate (MA) and acrylonitrile (AN) onto acacia cellulose was carried out using free radical initiating process in which ceric ammonium nitrate (CAN) was used as an initiator. The optimum grafting yield was determined by the certain amount of acacia cellulose (AGU), mineral acid (H₂SO₄), CAN, MA, and AN at 0.062, 0.120, 0.016, 0.397, and 0.550 mol L^?1, respectively. The poly(methyl acrylate‐co‐acrylonitrile)‐grafted acacia cellulose was obtained at 55°C after 2‐h stirring, and purified acrylic polymer‐grafted cellulose was characterized by FTIR and TG analysis. Therein, the ester and nitrile functional groups of the grafted copolymers were reacted with hydroxylamine solution for conversion into the hydroxamic acid and amidoxime ligands. The chelating behavior of the prepared ligands toward some metal ions was investigated using batch technique. The metal ions sorption capacities of the ligands were pH dependent, and the sorption capacity toward the metal ions was in the following order: Zn²⁺ > Fe³⁺ > Cr³⁺ > Cu²⁺ > Ni²⁺. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of tetramethylpolycarbonate‐block‐poly(styrene‐co‐acrylonitrile) copolymers containing various amounts of acrylonitrile on the interfacial properties of polycarbonate and poly(styrene‐co‐acrylonitrile) blends

Tetramethylpolycarbonate‐block‐poly(styrene‐co‐acrylonitrile) (TMPC‐block‐SAN) block copolymers containing various amounts of acrylonitrile (AN) were examined as compatibilizers for blends of polycarbonate (PC) with poly(styrene‐co‐acrylonitrile) (SAN) copolymers. To explore the effects of block copolymers on the compatibility of PC/SAN blends, the average diameter of the dispersed particles in the blend was measured with an image analyzer, and the interfacial properties of the blends were analyzed with an imbedded fibre retraction technique and an asymmetric double‐cantilever beam fracture test. Reduction in the average diameter of dispersed particles and effective improvement in the interfacial properties was observed by adding TMPC‐block‐SAN copolymers as compatibilizer of PC/SAN blend. TMPC‐block‐SAN copolymer was effective as a compatibilizer when the difference in the AN content of SAN copolymer and that of SAN block in TMPC‐block‐SAN copolymer was less than about 10 wt%. Copyright © 2004 Society of Chemical Industry     

Surface modification of coir fibers. II. Cu(II)‐ IO initiated graft copolymerization of acrylonitrile onto chemically modified coir fibers

A study of the graft copolymerization of acrylonitrile (AN) onto chemically modified coir fibers was carried out using a CuSO₄ and NaIO₄ combination as the initiator in an aqueous medium in a temperature range of 50–70°C. The graft yield was influenced by the reaction time, temperature, concentration of CuSO₄, concentration of NaIO₄, and monomer concentration. Grafting was also carried out in the presence of inorganic salts and organic solvents. A combination of copper(II) and sodium periodate (Cu²⁺‐IO) in an aqueous medium with an IO concentration of 0.005 mol L^?1 and a Cu²⁺ concentration of 0.004 mol L^?1 produced optimum grafting. The chemically modified and AN grafted fibers were characterized by FTIR and scanning electron microscopy (SEM). The SEM studies revealed that grafting not only takes place on the surface of the fibers but also penetrates the fiber matrix. The tensile properties like the maximum stress at break and extension at break of untreated, chemically modified, and AN grafted coir fibers were evaluated and compared. The extent of absorption of water of untreated, chemically modified, and grafted coir fibers was determined. It was found that grafting of AN imparts hydrophobicity onto coir fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 75–82, 2002; DOI 10.1002/app.10221     

Synthesis,characterization, and antitumor activity of poly(maleic anhydride‐co‐vinyl acetate‐co‐acrylic acid)

The ternary copolymerization of maleic anhydride (MA), vinyl acetate (VA), and acrylic acid (AA) [P(MA‐co‐VA‐co‐AA)], which is considered to be an acceptor–donor–acceptor system, was carried out in 1,4‐dioxane with benzoyl peroxide as an initiator at 70°C under a nitrogen atmosphere. Constants of complex formation for the monomer systems in the study were determined by UV–visible (hydrogen‐bonding complex) and ¹H‐NMR (charge transfer complex) methods, respectively. The results show that polymerization of the P(MA‐co‐VA‐co‐AA) system proceeds by an alternating terpolymerization mechanism. It is shown that the synthesized copolymers have typical polyelectrolyte behavior, ability for reversible hydrolysis–anhydrization reactions, and semicrystalline structures. In these cases, including radical polymerization, and formation of semicrystalline structures, the hydrogen‐bonding effect plays a significant role. The in vitro cytotoxicities of the synthesized terpolymer and alternating copolymer were evaluated using Raji cells (human Burkitt lymphoma cell line). The antitumor activities of prepared anion‐active copolymers were studied using methyl–thiazol–tetrazolium colorimetric assay and 50% of the cytotoxic dose of each copolymer and terpolymer were calculated. Hydrolyzed P(MA‐co‐VA‐co‐AA) and P(MA‐alt‐AA) copolymers have sufficiently high antitumor activity, which depends on the amount of hydrogen‐bonding carboxylic groups and their regular distribution in the side chain of functional macromolecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3425–3432, 2006     

Synthesis,physical properties,and crystallization of optically active poly(L‐phenyllactic acid) and poly(L‐phenyllactic acid‐co‐L‐lactic acid)

Optically active poly(L ‐phenyllactic acid) (Ph‐PLLA), poly(L ‐lactic acid) (PLLA), and poly(L ‐phenyllactic acid‐co‐L ‐lactic acid) with weight‐average molecular weight exceeding 6 × 10³ g mol^?1 were successfully synthesized by acid catalyzed direct polycondensation of L ‐phenyllactic acid and/or L ‐lactic acid in the presence of 2.5–10 wt % of p‐toluenesulfonic acid. Their physical properties and crystallization behavior were investigated by differential scanning calorimetry, thermogravimetry, and polarimetry. The absolute value of specific optical rotation ([α]) for Ph‐PLLA (?38 deg dm^?1 g^?1 cm³) was much lower than that of [α] for PLLA (?150 deg dm^?1 g^?1 cm³), suggesting that the helical nature was reduced by incorporation of bulky phenyl group. PLLA was crystallizable during solvent evaporation, heating from room temperature, and cooling from the melt. Incorporation of a very low content of bulky phenyllactyl units even at 4 mol % suppressed the crystallization of L ‐lactyl unit sequences during heating and cooling, though the copolymers were crystallizable for L ‐phenylactyl units up to 6 mol % during solvent evaporation. The activation energy of thermal degradation (ΔE_td) for Ph‐PLLA (200 kJ mol^?1) was higher than that for PLLA (158 kJ mol^?1). The ΔE_td for the copolymers increased with an increase in L ‐phenyllactyl unit content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of acrylonitrile‐ethyl methacrylate copolymers and the effect of LiClO4 salt on electrical properties of copolymer films

Copolymers of poly(acrylonitrile‐co‐ethyl methacrylate), P(AN‐EMA), with three different EMA content and parent homopolymers were synthesized by emulsion polymerization. The chemical composition of copolymers were identified by FTIR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The thermal properties of copolymers were modified by changing the EMA content in copolymer compositions. Various amounts of LiClO₄ salt loaded (PAN‐co‐PEMA) copolymer films were prepared by solution casting. The dielectric properties of these films at different temperatures and frequencies were investigated. It was found that the dielectric constant and ac‐conductivity of copolymer films were strongly influenced by the salt amounts and EMA content in copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Molecular and thermal studies of carbon fiber precursor polymers with low thermal‐oxidative stabilization characteristics

In this investigation, terpolymers, copolymers, and homopolymer of acrylonitrile with dimethylaminopropyl acrylamide (DMAPA), itaconic acid (IA) viz., poly(acrylonitrile‐ran‐3‐dimethylaminopropyl acrylamide‐ran‐itaconic acid) [P(AN‐DMAPP‐IA)], poly(acrylonitrile‐co‐3, dimethylaminopropyl acrylamide) [P(AN‐DMAPP)] were synthesized with varying amounts of comonomers using solution polymerization process. The chemical structure, composition, bonding network were determined employing infrared, 1H and, 13‐carbon nuclear magnetic resonance spectroscopic techniques. Molecular characteristics of as‐synthesized polymers such as different kinds of average molecular weights, molecular weight distribution were estimated applying solution viscometry and size exclusion chromatography. The influence of comonomers (DMPAA, IA) on the thermal stabilization characteristics of acrylonitrile terpolymers in comparison with copolymers and homopolymers of acrylonitrile were studied using differential scanning calorimetry (DSC), hyphenated thermal techniques (thermal gravimetry coupled with differential thermal analyzer).The DSC curves of P(AN‐DMAPP‐IA) exhibit a distinct broader bimodal peaks with thermal exotherm initiating at as low as 165 °C, and followed by two peaks with temperature difference of 42 °C, releasing the evolved heat at a release rate of 0.7–0.11 J g^?1s^?1over 10 min as compared to 1.2, 7.5 J g^?1s^?1 in 4.5, 2 min as observed in P(AN‐DMAPP), polyacrylonitrile, respectively. The thermal stability of P(AN‐DMAPP‐IA) and P(AN‐DMAPP), as evidenced by TGA‐DTA was found to be higher than PAN homopolymers. Specific heat capacity measurements confirmed the DSC results. Bulk densities of P(AN‐DMAPP‐IA) were in the range 0.31–0.35 g/cc. These results confirm the low‐temperature stabilization characteristics and suitability of P(AN‐DMAPP‐IA) as low cost carbon fiber precursor polymers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46381.     

Synthesis and properties of poly(acrylonitrile‐co‐p‐trimethylsilylstyrene) and poly(acrylonitrile‐co‐p‐trimethylsilylstyrene‐co‐styrene)

Copolymerization of acrylonitrile (AN) with p‐trimethylsilylstyrene (TMSS) was carried out at 60°C in bulk and in solution in the presence of 2,2′‐azobisisobutyronitrile (AIBN). The reactivity ratios of AN (M₁) and TMSS (M₂) were determined to be r₁ = 0.068 and r₂ = 0.309. The effects of the AIBN concentration and that of the chain transfer agent CCl₄ on the molecular weights (MWs) of the copolymers were investigated. An increase in the concentrations of AIBN or CCl₄ in solution led to a decrease in MW. Poly(AN‐co‐TMSS‐co‐St) was synthesized in solution using AIBN as the initiator. The molar fraction of AN was 0.415, while the molar ratio of TMSS/St varied from 1 : 1 to 1 : 9. The transition temperatures and thermal and thermooxidative stabilities of poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) were investigated. The differential scanning calorimeter technique was used to determine the compatibility of the poly(AN‐co‐TMSS) and poly(AN‐co‐TMSS‐co‐St) with commercial poly(AN‐co‐St). All the blends show a single glass transition temperature, which indicates the compatibility of the blend components. The surface film morphology of the blends mentioned above was examined by X‐ray photoelectron spectroscopy. The data obtained indicate that the silicon‐containing copolymer is concentrated in the surface layer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1920–1928, 2000     

Preparation of hydrolysis of poly(acrylonitrile‐co‐methyl acrylate) membranes via thermally induced phase separation: Effects of hydrolysis conditions and additives

In this work, melt processable poly(acrylonitrile‐co‐methyl acrylate) [(P(AN‐MA)] was hydrolyzed first and then formed into microporous membrane via thermally induced phase separation. In order to optimize the hydrolysis condition and fabricate hydrophilic PAN‐based membranes, a series of hydrolysis experiments were performed to indicate the influence of hydrolysis temperature, alkaline species and time. The structure and properties of hydrolyzed P(AN‐MA) [H‐P(AN‐MA)] membranes were also investigated. It was found that with the increase of hydrolysis temperature, pure water flux (PWF) increased first and then decreased. When the hydrolysis temperature increased to 30 °C, the PWF of the H‐P(AN‐MA) membrane was up to the maximum of 6712.7 L/m² h, which increased by 1661.6 L/m² h, compared with the P(AN‐MA) membranes. When 1 wt % sodium dodecyl sulfate (SDS) was incorporated into the diluents, the PWF increased dramatically, especially in high hydrolysis temperature. When the hydrolysis temperature was up to 70 °C, the PWF of H‐P(AN‐MA) membranes containing 1 wt % SDS increased by 2.3 times compared to the sample without SDS under the same condition. With 2 wt % amino functionalized multi‐walled carbon nanotubes (MWCNTs‐NH₂) employed as the additive, the tensile strength was up to 4.55 MPa. When 1 wt % SDS and 0.5 wt % MWCNTs‐NH₂ were mixed together, the bovine serum albumin rejection increased from 31.2% to 40.9%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46380.     

Structure and properties of poly(acrylonitrile‐co‐methyl acrylate) membranes prepared via thermally induced phase separation

Poly(acrylonitrile‐co‐methyl acrylate) [(P(AN‐MA)] microporous membranes were prepared via a thermally induced phase separation (TIPS) process by using γ‐butyrolactone (γ‐BA) and glyceryl triacetate (GTA) as the mixed diluent. The purpose of this work is to investigate the effects of the γ‐BA content, P(AN‐MA) concentration, and cooling rate on the structure and properties of P(AN‐MA) membranes. A lacy structure with high connectivity was formed with 50 wt % γ‐BA, and 50 wt % GTA comprising the mixed diluent. With an increase in the γ‐BA content, the pore structure acquires semi‐closed or completely closed cell‐like morphologies. The different phase separation mechanisms greatly influence the mechanical properties of the P(AN‐MA) membranes. P(AN‐MA) membranes with a lacy structure possess better tensile strength than those with semi‐closed or completely closed cell‐like structures. The membrane pore size grows larger when the TIPS process utilizes a higher γ‐BA content and a lower cooling rate. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43444.     

Kinetic study on peroxidation of benzaldehyde by polymer‐immobilized cobalt‐EDTA complex

Polymer‐immobilized cobalt‐EDTA complex was prepared by grafted copolymerization of methacrylic acid (MAA) and acrylonitrile (AN initiated by redox initiation of EDTA‐2Na (Ethylenediamine tetraacetic acid disodium salt) with ceric ion (Ce²⁺)). High yield and selectivity for peroxidation of benzaldehyde were obtained when using the polymer‐immobilized cobalt‐EDTA complex as a catalyst. With the concentration of benzaldehyde increasing, the concentration of perbenzoic acid was increased from 0.38M to 0.98M, but yield of perbenzoic acid decreased from 0.76M to 0.65M. With the amount of the polymer support increased, the yield of perbenzoic acid increased from 70% to 82%. The selectivity remained about 82% in the various amounts of the polymer support. The activation energy of peroxidation of benzaldehyde was 43.4 KJ/mole. The expression of the reaction rate was: r_i = k[RCHO][polymer support]^0.5. A mechanism for peroxidation of benzaldhyde catalysed by polymer‐immobilized cobalt‐EDTA complex was proposed in this investigation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3248–3257, 2001     

Retention properties of arsenate anions of water‐soluble polymers by a liquid‐phase polymer‐based retention technique

The retention properties of arsenic ions from an aqueous solution by water‐soluble cationic polymers and cationic–anionic copolymers were investigated. Poly[(3‐methacryloylamine)propyl]trimethylammonium chloride [P(ClMPTA)] and poly[(3‐methacryloylamine)propyl]trimethylammonium chloride–co–acrylic acid [P(ClMPTA‐co‐AA] were synthesized by radical polymerization. The copolymers were prepared with feed mole ratios of ClMPTA to AA of 1 : 1, 1 : 2, and 2 : 1. The copolymer compositions were evaluated by FTIR spectroscopy, TG‐DSC, and elemental analysis. The liquid‐phase polymer‐based retention (LPR) technique was used. This technique consists of retention of arsenate anions by the quaternary ammonium salt of a water‐soluble polymer in a filtration membrane cell. It was shown that the polymers could bind H₂AsO species from an aqueous solution more selectively at pHs of 6 and 8, than at a pH of 4. An increase in the polymer concentration was associated with increased retention capacity but not linearly. At the highest concentration the influence of pH was better observed. Investigation of copolymers showed the concerted action of polycations and polyanions on the ability to retain arsenic. At the lowest pH, the role of ionic strength of the media had a remarkable effect on the retention ability, independently of copolymer composition. At a pH of 6 a copolymer polycation/polyanion composition of 2 : 1 had the highest selective effect. At a pH of 8, a nonequimolar copolymer composition showed the same efficiency for the retention of arsenate species. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2677–2684, 2006     

Carbon‐13 nuclear magnetic resonance investigation of styrene–α‐methylstyrene copolymers

A copolymer based on α‐methylstyrene (AMS) was investigated by nuclear magnetic resonance (NMR). The styrene‐co‐α‐methylstyrene (SAMS) was analyzed by solution and solid‐state NMR techniques. Three copolymers of SAMS with different compositions presented a particular behavior. The solution results showed the copolymer microstructure and the AMS content. The carbon‐13 spectra of SAMS C indicated that the AMS CH₃ signal was detected at three distinct chemical shifts, because of the different comonomer‐sequences distribution. The proton spin–lattice relaxation time in the rotating frame (Tρ) parameter was chosen because it permits the evaluation of changes in the molecular mobility. The values of Tρ found for the copolymers confirmed the random distribution in the samples. The copolymer with a low quantity of AMS (1.7%), when analyzed by this relaxation parameter, showed lower values that were interpreted as an antiplasticization effect. The SAMS copolymer with a higher AMS quantity showed a plasticization effect. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 261–266, 2001     

Chemical modification of pineapple leaf fiber: Graft copolymerization of acrylonitrile onto defatted pineapple leaf fibers

Graft copolymerization of acrylonitrile (AN) onto defatted pineapple leaf fiber (PALF) was studied using a CuSO₄ and KIO₄ combination as an initiator in an aqueous medium in the temperature range 30–50⁰C. The effects of the concentration of potassium periodate, CuSO₄, and monomer on the graft yield were investigated. The effects of time, temperature, amount of some inorganic salts, and organic solvents on the graft yield are also reported. A combination of Cu⁺²—IO in an aqueous medium with an IO concentration of 0.005 mol L⁻¹ and Cu⁺² concentration of 0.002 mol L⁻¹ produced optimum grafting for use of 0.1 g defatted PALF with a fiber‐to‐liquor ratio of 1:50 at 50⁰C for 2 h. However, KIO₄ and CuSO₄ failed to induce polymerization of AN in the presence of PALF when used separately. FTIR and thermogravimetric analysis of the defatted and AN‐grafted PALF were carried out. Grafting improved the thermal stability of PALF. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3035–3043, 2000     

Synthesis of poly(acrylonitrile‐co‐divinylbenzene‐co‐vinylbenzyl chloride)‐derived hypercrosslinked polymer microspheres and a preliminary evaluation of their potential for the solid‐phase capture of pharmaceuticals

Poly[acrylonitrile (AN)‐co‐divinylbenzene (DVB)‐co‐vinylbenzyl chloride (VBC)] terpolymers were synthesized by precipitation polymerization in the form of porous polymer microspheres. The poly(AN‐co‐DVB‐co‐VBC) polymers were then hypercrosslinked, via a Friedel‐Crafts reaction with FeCl₃ in nitrobenzene, to provide a significant uplift in the specific surface areas of the polymers. FTIR spectra of the hypercrosslinked poly(AN‐co‐DVB‐co‐VBC)s showed that the chloromethyl groups derived from VBC were consumed by the Friedel‐Crafts reactions, which was consistent with successful hypercrosslinking. Hypercrosslinking installed a number of new, small pores into the polymers, as evidenced by a dramatic increase in the specific surface areas upon hypercrosslinking (from ～530 to 1080 m² g^?1). The hypercrosslinked polymers are very interesting for a range of applications, not least of all for solid‐phase extraction (SPE) work, where the convenient physical form of the polymers (beaded format), their low mean particle diameters, and narrow particle size distributions, as well as their high specific surface areas and polar character (arising from the AN residues), make them attractive candidates as SPE sorbents. In this regard, in a preliminary study one of the hypercrosslinked polymers was utilized as an SPE sorbent for the capture of the polar pharmaceutical diclofenac from a polar environment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45677.