Ionic absorption of polypropylene functionalized by surface grafting and reactions

Plasma-induced surface graft copolymerization of acrylic acid on polypropylene fibers and the subsequent reactions of the grafted carboxylic groups are reported. The extents of grafting was controlled by the plasma conditions. Reactions of the carboxylic acid with selected amines resulted in ion-exchanging and chelating functionalities. In general, ion adsorption is enhanced by higher levels of grafting and by raising temperature during adsorption. The adsorption level and preferences among ions of these functionalized fibers depend on the structure of the functional groups, i.e., the structure of the spacer and terminal groups. The carboxylic acid groups of the PP-g-AA fibers which behave like weakly acidic ion-exchangers are attributed to the low metal ion adsorption and the lack of ion preference. The F1 fibers with flexible  CH₂CH₂ spacer and small terminal  OH in the functional group exhibits highest ion adsorption among all functionalized fibers studied here. With benzene spacers, metal adsorption can be enchanced by the electron-donating nature of the terminal group. With the same ester end group in the functional structure, F3 fibers which contain benzene ring spacers show higher ion adsorption than F4 and F5 which have CH₂ and NH spacers, respectively. The ion preference and adsorption ability of the functionalized fibers, i.e., equilibrium binding constants (K_b) and saturation constants (K_s) derived from adsorption isotherms, also depend on the functional group structures. K_b increases with increasing grafting yield, increasing the electron donor atom in either terminal bonds or spacer, and reducing the steric hindrance of spacer. The K_s values are affected by the accessibility of functional groups, the size of spacer, and the terminal group structure. © 1997 John Wiley & Sons, Inc.     

Microwave-Assisted Graft Copolymerization of Cellulosic Fibers for Removal of Heavy Metal Ions from Aqueous Solution

Functional materials obtained from cellulosic biofibers have gained attention due to the growing demand for them in the field of wastewater remediation. In view of the technological significance of functionalized cellulosic biofibers in wastewater treatment, the present study is a green approach to functionalized cellulosic fibers through graft copolymerization under microwave irradiation. The grafted cellulosic polymers were subsequently subjected to heavy metal ion adsorption studies in order to assess their application in wastewater remediation. The effects of pH, contact time, temperature, and metal ion concentration were studied in batchwise adsorption experiments. The Langmuir, Freundlich, and Tempkin models were used to show the adsorption isotherms. The maximum monolayer capacities, q _m. calculated using the Langmuir isotherm for Zn²⁺, Cd²⁺, and Pb²⁺ were found to be 37.79, 69.68, and 96.81 mg/g respectively. The thermodynamic parameter ΔH° and ΔG° values for metal ion adsorption on functionalized cellulosic fibers showed that adsorption process was spontaneous as well as exothermic in nature.     

Preparation of quaternized dimethylaminoethylmethacrylate grafted nonwoven fabric for the removal of phosphate

Dimethylaminoethylmethacrylate (DMAEMA) grafted polyethylene/polypropylene (PE/PP) nonwoven fabric was prepared by radiation-induced graft polymerization. Grafting conditions were optimized and about 150% DMAEMA grafted samples were used for further experiments. DMAEMA graft chains were later quaternized with dimethyl sulphate for the removal of phosphate ions. Adsorption experiments were conducted with quaternized DMAEMA grafted fabric for phosphate removal at low (0.5–25 ppm) and high phosphate concentrations (50–1000 ppm). Adsorbed phosphate amounts at pH 7 were found to be 63 mg phosphate/g polymer and 512 mg phosphate/g polymer for low (25 ppm) and high phosphate concentrations (1000 ppm) respectively showing the efficiency of the adsorbent material in removing phosphate. The pH effect on phosphate adsorption showed that the quaternized DMAEMA grafted nonwoven fabric can adsorb phosphate over a wide pH range (5.00–9.00) indicating that adsorbent material can effectively remove different forms of phosphate ions, namely H₂PO₄^?, HPO₄^2? and PO₄^3? in aqueous solution at this pH range where the species exist. Competitive adsorption experiments were also carried out with two concentration levels at pH 7 to investigate the effect of competing ions. Phosphate adsorption on quaternized DMAEMA grafted nonwoven fabric was found to be higher than the other competing ions at two concentration levels. At high concentration level, the adsorption order was phosphate>nitrite>bromide>sulphate>nitrate whereas at low concentration level, the order was phosphate?sulphate>bromide>nitrite>nitrate.     

Adsorption properties for metal ions of waste poly(p‐phenylene terephthalamide) fiber after chemical modification

Waste poly(p‐phenylene terephthalamide) fibers (PPTA) were chemically modified through nitration and nitro‐reduction reactions to obtain nitro‐ and amino‐containing fibers and used as adsorbents for metal ions. The structures of the modified fibers were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and thermogravimetric (TG) analysis. Metal ions, such as Ni²⁺, Pb²⁺, Cu²⁺, and Hg²⁺, were used to determine the adsorption capacities of the PPTA fibers before and after modification in aqueous solutions. The results showed that the modification improved the adsorption capability of fibers and extraction ratio of metal ions significantly. The adsorption mechanism of modified PPTA fibers for metal ions was proposed. The adsorption processes of Ni²⁺, Pb²⁺, and Cu²⁺ followed well a pseudosecond‐order model onto PPTA‐NH₂. The Langmuir and Freundlich models were employed to fit the isothermal adsorption. The results revealed that the linear Langmuir isotherm model is better‐fit model to predict the experimental data. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of tapioca cellulose-based poly(hydroxamic acid) ligand for heavy metals removal from water

A graft copolymerization was performed using free radical initiating process to prepare the poly(methyl acrylate) grafted copolymer from the tapioca cellulose. The desired material is poly(hydroxamic acid) ligand, which is synthesized from poly(methyl acrylate) grafted cellulose using hydroximation reaction. The tapioca cellulose, grafted cellulose and poly(hydroxamic acid) ligand were characterized by Infrared Spectroscopy and Field Emission Scanning Electron Microscope. The adsorption capacity with copper was found to be good, 210 mg g^?1 with a faster adsorption rate (t_1/2 = 10.5 min). The adsorption capacities for other heavy metal ions were also found to be strong such as Fe³⁺, Cr³⁺, Co³⁺ and Ni²⁺ were 191, 182, 202 and 173 mg g^?1, respectively at pH 6. To predict the adsorption behavior, the heavy metal ions sorption onto ligand were well-fitted with the Langmuir isotherm model (R² > 0.99), which suggest that the cellulose-based adsorbent i.e., poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability was checked by the sorption/desorption process for six cycles and the sorption and extraction efficiency in each cycle was determined. This new adsorbent can be reused in many cycles without any significant loss in its original removal performances.     

Radiation-induced graft polymerization and sulfonation of glycidyl methacrylate on to porous hollow-fiber membranes with different pore sizes

An epoxy group containing monomer, glycidyl methacrylate, was grafted on to a porous hollow-fiber membrane, made of polyethylene, whose different pore sizes ranged from 0.2 to 0.5 μm. The resulting epoxy group was converted into a sulfonic acid group as a cation-exchange group to capture metal ions. The porous network was retained after grafting and subsequent sulfonation because the poly-GMA chains invaded the polymer matrix. An increase in the SO₃H group density of the graft chain decreased the permeability of pure water because the graft chains expanded toward the pore interior due to their mutual electrostatic repulsion. The ion-exchange adsorption of Pb ions during the permeation of a Pb(NO₃)₂ solution through the pores edged by the cation-exchange graft chains was observed with a negligible diffusional mass-transfer resistance.     

Development and tailoring of amino-functionalized activated carbon based Cucumerupsi manni Naudin seed shells for the removal of nitrate ions from aqueous solution

The removal of nitrate ions with ethylenediamine (EDA)-functionalized activated carbon (AC-NH₂) was studied in this work. Activated carbon prepared from Cucumerupsi manni Naudin seed shells using ZnCl₂ (ACZ) was functionalized with EDA via a nitric acid oxidation followed by acyl chlorination and amidation process. The effect of pH, contact time, initial concentration and co-existing ions on the adsorption of nitrate ions have been investigated. The FTIR and elemental analysis revealed that amino groups were successfully grafted onto the ACZ after functionalization. The surface area and average pore of ACZ were found to be 1008.99 m²/g and 2.02 nm respectively. However, it was noticed that, after functionalization (AC-NH₂), its surface area decreases to 113.43 m²/g meanwhile, its pore diameter increases to 2.48 nm. The experimental results of adsorption showed that AC-NH₂ exhibit excellent nitrate ions uptake performance compared to ACZ which is attributed to the presence of the grafted amino groups on the ACZ. Nitrate adsorption follows pseudo-first-order kinetic model while the equilibrium adsorption data was best fitted the Freundlich isotherm suggesting that the adsorption process was predominated by physisorption. This study demonstrates that the prepared AC-NH₂ is a promising adsorbent for nitrate ions removal from aqueous media.     

Functionalized Cellulosic Fibers for Removal of Toxic Metal Ions From Contaminated Water

Functionalization of cellulosic okra fibers was carried out by graft copolymerization of acrylamide in the presence of ascorbic acid and hydrogen peroxide as redox initiator in aqueous medium. Different reaction parameters such as time, temperature, initiator concentration, and monomer concentration were optimized to obtain the maximum graft yield. The graft copolymerized fibers were characterized by FT-IR, TGA, and X-ray diffraction techniques. Further, chemically modified fibers were used for removal of Zn²⁺ and Cd²⁺ toxic metal ions from contaminated water. The effect of pH, contact time, and metal ion concentration was studied in batch mode experiments. The kinetics of adsorption were studied using pseudo-first and pseudo-second-order kinetic models. The adsorption isotherm was studied using Langmuir and Freundlich isotherm models. The Langmuir model was found to fit the equilibrium data well.     

Synthesis and swelling behavior of amphiphilic comb‐like branched polymer (AA‐co‐CMS)‐g‐PMMA

Copolymerization of acrylic acid and p‐chloromethylstyrene (p‐CMS) in dioxane initiated with α,α′‐azobisisobutyronitrile was carried out to produce macroinitiator P(AA‐co‐CMS) containing PhCH₂Cl group at 65°C. Then methyl methacrylate was grafted onto P(AA‐co‐CMS) backbone using PhCH₂Cl group as an initiation site and FeCl₂/triphenyl phosphine complex as a catalyst. The resulted copolymer (AA‐co‐CMS)‐g‐PMMA with a comb‐like branched structure has a hydrophilic backbone (PAA) and hydrophobic side chains (PMMA). Compositions and structures of macroinitiator and the grafted product of P(AA‐co‐CMS)‐g‐PMMA were determined by ¹H‐NMR, infrared (IR), and gel permeation chromatography (GPC). The average graft number, the average length of branch chains, the graft ratio, and the graft efficiency were investigated. The swelling behavior of the comb‐like branched polymer was also investigated. The gradual increase of swelling ratios was accompanied by an increase of pH and temperature. The kinetic exponents indicated that the swelling transport mechanisms transformed from Fickian diffusion to non‐Fickian transport as the decreasing pH. Copyright © 2009 John Wiley & Sons, Ltd.     

Dispersion mechanisms of comb‐type superplasticizers containing grafted poly(ethylene oxide) chains

This paper discusses the influence of graft chain length and dosage of comb‐type superplasticizers on adsorption and dispersion mechanisms, and their subsequent effect on the fluidity of concentrated limestone suspensions. Contrary to the results obtained from interparticle potential calculations, the fluidity of concentrated suspension is improved by the use of comb‐type polymers having shorter grafted chain length. The dispersion mechanism of comb‐type polymers in a concentrated suspension is evaluated from the perspective of molecular structure, the amount of adsorbed polymer, and the amount of entrapped water in the clusters of CaCO₃ particles. Furthermore, the addition of certain soluble salts, which can effect the concentration of Ca²⁺ in liquid phase of CaCO₃ suspensions, has been observed to decrease the adsorption of comb‐type polymers on CaCO₃. Thus, the polymer adsorption process on solid surfaces can be selectively influenced by certain types of ions.     

Preparation of Iminoacetic Acid-type Composite Chelating Material IAA-PEI/SiO2 and Preliminary Studies on Chelating Adsorption Property towards Heavy Metal Ions

Polyamine polyethyleneimine (PEI) was first grafted on the surfaces of micro-sized silica gel particles in the manner of the coupling graft (the manner of “grafting to”), forming the grafting particles PEI/SiO₂. Subsequently, via a polymer reaction, the nucleophilic substitution reaction between the primary and secondary amino groups of the grafted PEI macromolecule and chloroactic acid (CAA), iminoacetic acid groups were bonded onto the grafted PEI chains, and an iminoacetic acid (IAA)-type composite chelating material, IAA-PEI/SiO₂, was formed. In this work, the preparation process of IAA-PEI/SiO₂ particles was mainly researched, and the effects of the main factors on the polymer reaction, i.e., the nucleophilic substitution reaction, were examined emphatically. The adsorption behavior of IAA-PEI/SiO₂ particles towards several kinds of heavy metal ions was preliminarily evaluated. The experiments results show that it is feasible to introduce IAA groups onto PEI/SiO₂ particles via the substitution reaction between CAA and the amino groups of the grafted PEI. The reaction rate is affected greatly by the feed ratio of the amino group of PEI to CAA, so the substitution reaction between CAA and the amino groups of the grafted PEI is a bimolecular nucleophilic substitution reaction (S_N2). The reaction temperature and the used amount of acid-acceptor NaHCO₃ affect the bonding rate of IAA groups greatly. The fitting temperature was 60°C, and 1:1 of the molar ratio of NaHCO₃ to CAA was an appropriate amount of acid-acceptor NaHCO₃. Under the above optimal reaction conditions and with 3:1 molar ratio of amino group of PEI to CAA, 72% of the IAA group bonding rate (it is based on the hydrogen atoms in the primary and secondary amino groups of the grafted PEI) in 8 h can be reached. The composite chelating material IAA-PEI/SiO₂ possesses a strong chelating adsorption ability for heavy metal ions because of the increase of the ligands and formation of stable five-membered chelate rings.     

Preparation of PSSS‐grafted polysulfone microfiltration membrane and its rejection and removal properties towards heavy metal ions

3‐Hydroxy‐N,N‐diethylaniline (HDEA) as a tertiary aromatic amine was introduced onto the surface of chloromethylated polysulfone (CMPSF) microfiltration membrane through modification reaction, resulting in the modified membrane PSF‐DEA. A redox surface‐initiating system (DEA/APS) was constituted by the bonded tertiary aromatic amine group DEA and ammonium persulfate (APS) in aqueous solution, and so, the free radicals formed on the membrane initiated sodium p‐styrenesulfonate (SSS) as an anionic monomer to produce graft polymerization, getting the grafting‐type composite microfiltration membrane, PSF‐g‐PSSS membrane. Subsequently, the adsorption property of PSF‐g‐PSSS membrane for three heavy metal ions, Pb²⁺, Zn²⁺, and Hg²⁺ ions, was fully examined, and the rejection performance of PSF‐g‐PSSS membrane towards the three heavy metal ions was emphatically evaluated via permeation experiments. The experimental results show that by the initiating of the surface‐initiating system of DEA/APS, the graft polymerization can smoothly be carried out under mild conditions. PSF‐g‐PSSS membrane as a functional microfiltration membrane has strong adsorption ability for heavy metal ions by right of strong electrostatic interaction (or ion exchange action) between the anionic sulfonate ions on the membrane and heavy metal ions. The order of adsorption capacity is Pb²⁺ > Zn²⁺ > Hg²⁺, and the adsorption capacity of Pb²⁺ ion gets up to 2.18 μmol/cm². As the volume of permeation solutions, in which the concentrations of the three metal ions are 0.2 mmol/L, are in a range of 50 to 70 mL, the rejection rate of PSF‐g‐PSSS membrane for the three heavy metal ions can reach a level of 95%, displaying a fine rejection and removing performance towards heavy metal ions.     

改性PTFE纤维金属配合物的制备及其光催化降解性能

使用聚丙烯酸接枝改性聚四氟乙烯(PAA-g-PTFE)纤维分别与Fe³⁺及其与Cu²⁺的混合物反应制备改性PTFE纤维铁和铁铜双金属配合物, 并分别使用傅里变换叶红外(FTIR)光谱和紫外-可见(UV-Vis)漫反射光谱(DRS)对两种配合物的化学结构和光吸收性能进行表征. 然后将两种配合物分别作为非均相光Fenton 反应催化剂应用于典型偶氮染料活性蓝222氧化降解反应中, 考察和比较了二者在不同pH介质中对降解反应的催化作用. 结果表明, 在有或无Cu²⁺的存在条件下, 一个Fe³⁺能够与三个PAA-g-PTFE表面的6个羧基发生反应形成配合物, 并且它们在紫外和可见光区表现出好的光吸收特性. 当两种金属离子共存时Cu²⁺比Fe³⁺更容易与PAA-g-PTFE发生配位反应形成铁铜双金属配合物. 在可见光辐射下PAA-g-PTFE铁配合物对不同pH水溶液中染料降解反应均表现出显著的催化作用, 但是溶液pH的升高不利于配合物催化活性的发挥. 而配合物中铁离子含量提高特别是引入Cu²⁺作为助金属离子能够较大幅度地改善其在高pH范围内的催化活性和重复利用性.     

The characteristic fragment ions and visualization of cationic starches on pulp fiber using ToF‐SIMS

Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was used to investigate the distribution of cationic starch on pulp fiber. To identify the characteristic fragment ions of the cationic starches, deuterium‐labeled cationic starches were prepared and analyzed using ToF‐SIMS. The starch 2‐hydroxypropyltrimethylammonium chloride derivative generated characteristic fragments at m/z 58 and 59, which were identified as [H₂C?N(CH₃)₂]⁺ and [N(CH₃)₃]^+·, respectively. The fragmentation patterns were also suggested. From the imaging analysis, the adsorption of the cationic starch on fibers was uneven on individual fibers, as well as between fibers. This may have been on account of fiber morphology and structure. On examining scanning electron microscope (SEM) images, the quaternary ammonium starch derivative (QS) did not penetrate the fiber. No migration of cationic starch was observed under various drying conditions. Copyright © 2007 John Wiley & Sons, Ltd.     

The influence of variant PE‐b‐PEO segments on physical properties of LLDPE graft copolymers

A method was adopted to fix a series of polymers of PE‐b‐PEO with different PEO/PE segments on the chains of LLDPE. Maleic anhydride (MA) reacting with hydroxyl group of PE‐b‐PEO (mPE‐b‐PEO) was used as the intermediate. The structures of intermediates and graft copolymers were approved by ¹H NMR and FTIR. XPS analysis revealed a great amount of oxygen on the surface of grafted copolymers although the end group of PEO was fixed on the LLDPE chains through MA. Thermal properties of the graft copolymers as determined by differential scanning calorimetry (DSC) showed that PE segments in the grafted monomers could promote the heterogeneous nucleation of the polymer, increase T_c, and crystal growth rate. While the amorphous PEO segments which attached to the crystalline PE segments in LLDPE, impaired their ability to fit the crystal lattice, and depressed the crystallization of LLDPE backbones. In this study, it was also verified through the dynamic rheological data that increasing M_n of grafted monomers significantly increased the complex viscosity and enhanced the shear‐thinning behavior. Long‐branched chains formed by grafted monomers enhanced the complex moduli (G′ and G″) value and retarded relaxation rate. However, there were little influence on the rheological properties when increasing the amounts of PEO segments (or decreasing PE segments) of grafted monomers with similar molecular weight. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 506–515, 2008     

Preparation of amino-modified hydroxyapatite and its uranium adsorption properties

The amino-hydroxyapatite (HAP-NH₂) was synthesized by grafted amino functional groups onto hydroxyapatite. The uranium adsorption performance of HAP-NH₂ was studied under different conditions. The results indicated that HAP-NH₂ possessed high adsorption capacity (96 mg g⁻¹), wide pH values range (2–8) and fast adsorption rate (20 min). The adsorption kinetic and adsorption isotherm models of HAP-NH₂ revealed that the uranium adsorption process was belonged to chemical adsorption. Furthermore, the main forces between uranium ions and HAP-NH₂ were attributed to hydroxyl, amino and phosphorous functional groups.

     

Preparation, characterization of carboxylated bamboo fibers and their adsorption for lead(II) ions in aqueous solution

The present study was conducted to develop a simple and versatile method to prepare carboxylated bamboo fibers which can be applied as potential bio-adsorbent for metal ions removal due to the high content of carboxyl groups. The chemical modification of bamboo fibers with citric acid (CA) was carried out by friendly semi-dry oven method. The resulting products with carboxyl group content between 1.99 and 4.13 mmol/g were accessible by changing ultrasonic pretreatment time, reaction temperature, reaction time and the amounts of catalyst and citric acid in order to minimize cross-linking reaction and thereby maximize carboxyl groups content. The characterization of the resulting products confirmed that carboxyl groups were successfully grafted onto surface of bamboo fibers. Moreover, the carboxylated bamboo fibers could be applied as bio-adsorbent for the removal of lead(II) ions from aqueous solution. Results showed that the adsorption capacity of Pd²⁺ could reach 127.1 mg/g for carboxylated bamboo fibers with 4.13 mmol/g carboxyl group content prepared under the ultrasonic pretreatment for 20 min at the CA/bamboo fibers weight ratio of 4.0 in the catalyst amount of 30 wt% at 120 °C for 90 min and the carboxylated bamboo fibers exhibited highly efficient regeneration with no significant loss of adsorption capacity of lead ion after five repeated adsorption/desorption cycles.     

Graft Copolymerization on to Cellulose Using Binary Mixture of Monomers

The graft copolymerization of acrylonitrile (AN) and ethyl acrylate (EA) comonomers onto cellulose has been carried out using ceric ammonium nitrate (CAN) as an initiator in the presence of nitric acid at 35±0.1°C. The addition of ethyl acrylate as comonomer has shown a significant effect on overall and individual graft copolymerization of acrylonitrile on cellulose. The graft yield (%G_Y) and other grafting parameters viz. true grafting (%G_T), graft conversion (%C_G), cellulose number (Ng) and frequency of grafting (G_F) were evaluated on varying the concentration of comonomers from 6.0–30.0×10^?1 mol dm^?3 and ceric (IV) ions concentration from 2.5–25×10^?3 mol dm^?3 at constant feed composition (f_AN 0.6) and constant concentration of nitric acid (7.5×10^?2 mol dm^?3) in the reaction mixture. The graft yield (%G_Y) and other grafting parameters were optimal at 15×10^?1 mol dm^?3 concentration of comonomers and at 10×10^?3 mol dm^?3 concentration of ceric ammonium nitrate. The graft yield (%G_Y) and composition of grafted chains (F_AN) was optimal at a feed composition (f_AN) of 0.6. The energy of activation (Ea) for graft copolymerization has been found to be 16 kJ mol^?1. The molecular weight (Mw) and molecular weight distribution (Mw/Mn) of grafted chains was determined by GPC and found to be optimum at 15×10^?1 mol dm^?3 concentration of comonomer in the reaction mixture. The composition of grafted chains (F_AN) determined by IR method was used to calculate the reactivity ratios of monomers, which has been found to be 0.62 (r₁) and 1.52 (r₂), respectively for acrylonitrile (AN) and ethyl acrylate (EA) monomers used for graft copolymerization. The energy of activation for decomposition of cellulose and grafted cellulose was determining by using different models based on constant and different rate (β) of heating. Considering experimental observations, the reaction steps for graft copolymerization were proposed.     

Peroxide initiated maleic anhydride grafting: Structural studies on an ester‐containing copolymer and related substrates

Maleic anhydride (MAn) was grafted onto the low molecular weight esters methyl decanoate (MD) and methyl 2‐ethylhexanoate (MEH) using the free‐radical initiators Lupersol‐101 and ‐130; the esters were used as model compounds for the copolymer poly(ethylene‐co‐methyl acrylate). The grafted products in both cases were isolated from the unreacted ester and were subjected to extensive analysis using spectroscopic and chromatographic techniques. Analysis of the grafted material indicated the presence of one or more succinic anhydride (SAn) residues grafted to the ester. In the case of the multiply grafted material it has been established conclusively by ¹³C‐NMR using 2,3‐¹³C₂ labeled MAn that the multiple grafts exist as single units. A limited number of grafting experiments was performed on the copolymer in the melt and the graft‐modified copolymer was characterized spectroscopically. Single graft units were observed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1609–1618, 1999     

Polymer effect in graft polymerizations of acrolein onto imidazole-containing polymer

The graft polymerizations of acrolein (AL) onto an imidazole (Im)-containing polymer, such as a homopolymer of 4(5)-vinylimidazole (VIm) and several copolymers of VIm-4-vinylpyridine (VPy), VIm-1-vinyl-2-pyrrolidone (VPr), and VIm-styrene (St), have been studied in ethanol at 0°C. The degree of polymerization (P?_n) of the resulting polyacrolein graft depended on the number of Im units in the Im-containing polymer which produced a decrease in P?_n of grafted polyacrolein. The P?_n of the graft polyacrolein was determined to be in the range of 5-23. The rate of polymerization (R_p) was expressed by R_p = k(PVIm) (AL)². The graft polymerizability of the AL was influenced by the comonomer in the parent polymer, and was found to be in the order of VIm homopolymer > VIm-VPr copolymer > VIm-VPy copolymer > VIm-St copolymer. R_p was affected by the functional group around the Im group in the Im-containing polymer. These results were discussed by assuming the conformation of the parent polymer in ethanol.