Viscoelastic behaviour of vinylic copolymers of cellulose and their glass transition temperature by DSC

The viscoelastic response of some vinylic copolymers of cellulose prepared with vinyl acetatemethyl acrylate mixtures and with Ce(IV) ion as initiator, and native cellulose, were studied at 110 Hz in a range of temperatures from ?120–100°C. The viscoelastic spectrum of cellulose shows the β-relaxation that is not shown in its vinylic copolymers. We observed the same effect in the dielectric β-relaxation. For the vinylic copolymers of cellulose, one viscoelastic relaxation attributed to the α-relaxation of the grafted vinylic chains is observed. Some differences in the characteristics of this relaxation may be related to the composition of PVA/PMA vinylic side chains and to the ratio of cellulose in the copolymer. The plots of the Argand diagrams give us a better understanding of the viscoelastic behaviour of these materials. The results seem to indicate that the cellulose hinders the large-scale motions of the vinylic chains grafted onto it. The glass transition temperature (T_g) determined by differential scanning calorimetry (DSC) also shows the same fact: the T_g of the vinylic copolymers of cellulose are higher than both the T_g of polyvinyl acetate–polymethyl acrylate copolymers (PVA–PMA) without cellulose and the T_g of some blends of cellulose and the PVA–PMA whose composition was as similar as possible to the cellulosic copolymers. The importance of the covalent bonds between cellulose and the vinylic side chains in the structural transitions are revealed. The present results are compared with the dielectric α-relaxation that we described elsewhere. © 1993 John Wiley & Sons, Inc.     

Competitive removal of heavy metal ions by cellulose graft copolymers

The effect of composition of graft chains of four types cellulose graft copolymers on the competitive removal of Pb²⁺, Cu²⁺, and Cd²⁺ ions from aqueous solution was investigated. The copolymers used were (1) cellulose‐g‐polyacrylic acid (cellulose‐g‐pAA) with grafting percentages of 7, 18, and 30%; (2) cellulose‐g‐p(AA–NMBA) prepared by grafting of AA onto cellulose in the presence of crosslinking agent of N,N′‐methylene bisacrylamide (NMBA); (3) cellulose‐g‐p(AA–AASO₃H) prepared by grafting of a monomer mixture of acrylic acid (AA) and 2‐acrylamido‐2‐methyl propane sulphonic acid (AASO₃H) containing 10% (in mole) AASO₃H; and (4) cellulose‐g‐pAASO₃H obtained by grafting of AASO₃H onto cellulose. The concentrations of ions which were kept constant at 4 mmol/L in an aqueous solution of pH 4.5 were equal. Metal ion removal capacities and removal percentages of the copolymers was determined. Metal ion removal capacity of cellulose‐g‐pAA did not change with the increase in grafting percentages of the copolymer and determined to be 0.27 mmol metal ion/g_copolymer. Although the metal removal rate of cellulose‐g‐p(AA–NMBA) copolymer was lower than that of cellulose‐g‐pAA, removal capacities of both copolymers were the same which was equal to 0.24 mmol metal ion/g_copolymer. Cellulose did not remove any ion under the same conditions. In addition, cellulose‐g‐pAASO₃H removed practically no ion from the aqueous solution (0.02 mmol metal ion/g_copolymer). The presence of AASO₃H in the graft chains of cellulose‐g‐p(AA–AASO₃H) created a synergistic effect with respect to metal removal and led to a slight increase in metal ion adsorption capability in comparison to that of cellulose‐g‐pAA. All types of cellulose copolymers were found to be selective for the removal of Pb²⁺ over Cu²⁺ and Cd²⁺. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2034–2039, 2003     

1,2‐propanediol–cellulose–acrylamide graft copolymers

1,2‐Propanediol–cellulose–acrylamide graft copolymers (PCACs) were developed for enhanced oil recovery. They were prepared with acrylamide and 1,2‐propanediol (PDO)–cellulose, which was formed through the addition of glycols to cellulose by the Shotten–Baumann reaction between 3‐chloro‐1,2‐propanediol and cellulose. The graft copolymerization was initiated with a redox system between Ce⁴⁺ and glycols in cellulose. The infrared spectrum of PDO–cellulose had some characteristic absorption bands around 2960 (νC? H) and 1050 cm^?1 (νC? O) that also appeared for the PDO group and pyranose ring of cellulose, respectively. The rate of Ce⁴⁺ consumption by PDO–cellulose was investigated through the calculation of the overall kinetic constant from the slopes of ln(D ? D_R) versus time (where D is the absorbance and D_R is the absorbance of the original polysaccharide solution) The results showed that PDO–cellulose had high reactivity and that there were two mechanisms of oxidation by Ce⁴⁺ with PDO–cellulose. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3022–3029, 2004     

Tailoring of water‐soluble cellulose‐g‐ copolymers in homogeneous medium using single‐electron‐transfer living radical polymerization

Cellulose‐graft‐polyacrylamide and cellulose‐graft‐poly(N,N‐dimethylacrylamide) copolymers were prepared by single‐electron‐transfer living radical polymerization (SET‐LRP) in homogeneous medium. Cellulose macroinitiators for SET‐LRP, with different numbers of initiating sites along the cellulose backbone, were successfully synthesized by direct acylation of cellulose with 2‐bromoisobutyryl bromide in LiCl/dimethylacetamide. Dynamic light scattering revealed that cellulose macroinitiator molecules in dimethylsulfoxide (DMSO) exist primarily as individual chains with a certain amount of intermolecular aggregates. SET‐LRP of acrylamide and N,N‐dimethylacrylamide with the cellulose macroinitiators was carried out in DMSO solution. Formation of cellulose‐graft‐copolymers was confirmed using attenuated total reflectance Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopy, and the products were water‐soluble. High content of poly(N,N‐dimethylacrylamide) in the copolymers enhanced the thermal stability relative to that of cellulose. Scanning electron microscopy studies of cellulose‐based particles formed from the copolymers using the aerosol flow reactor method revealed spherical nanoscale structures. Copyright © 2011 Society of Chemical Industry     

Structure and properties of cellulose graft copolymers. II. Cellulose–styrene graft copolymers synthesized by the ceric ion method

Styrene was graft-copolymerized onto wood cellulose by the ceric ion method of Mino and Kaizerman. The grafting reaction was found to depend strongly on the concentration of ceric ion in the grafting system and maximum grafting occurred in a narrow range of concentration of initiator, 1.0 × 10^?3-1.8 × 10^?3 mol/l, at 58 ± 1°C. A pretreatment technique, developed to enhance the monomer diffusion into cellulose, was found to increase the grafting considerably. The structures of the cellulose-styrene graft copolymers were studied by hydrolyzing away the cellulose backbone to isolate the grafted polystyrene branches. The molecular weight and the molecular weight distributions of the grafted polystyrene were determined using gel permeation chromatography. The number-average molecular weight (M?_n) ranged from 23,000 to 453,000 and the polydispersity ratios (M?_w/M?_n) varied from 2.5 to 8.0. The grafting frequencies calculated from the per cent grafting and molecular weight data were of the order of 0.05–0.4 polystyrene branches per cellulose chain.     

Dynamic deposition of polyacids on porous membrane supports

Poly(acrylic acids), poly(styrenesulfonic acid), and their block and random copolymers were tested for their ability to form dynamic membranes on partially cured asymmetric cellulose acetate. Chemically modified porous polypropylene (Celgard) was also used as a support for poly(acrylic acid). Salt rejections, water fluxes, and streaming potentials of membranes were tested under hyperfiltration conditions. Sorption of the polyelectrolytes by the cellulose acetate supports was studied using spectrophotometric, ²²Na tracer, and electron microscopy techniques. The dynamic membrane formation was noted only for poly(acrylic acid) and for its 1:4:1 block copolymer with poly(styrenesulfonic acid). The uneffectiveness of other polyelectrolytes was discussed in terms of a negative zeta potential of cellulose acetate. The increase in salt rejection (R) due to the polyelectrolyte is strongly dependent on the initial R_i of the support. Sharp maxima in the ΔR -versus-R_i curves have been noted for R_i in the range of 40–55%. The most significant improvement in the hyperfiltration characteristics of cellulose acetate was attained with the 1:4:1 block copolymer. Flux of 17 gfd at 350 psi and R = 93% was obtained in short-term tests for a 0.1N feed solution. Long-term tests did not reveal any flux or salt rejection decline for membranes in which poly(acrylic acid) was complexed with phosphoramidic groups grafted onto Celgard.     

Preparation of cellulose graft copolymers having polypeptide side chains and their blood compatibility

Blood compatibility of cellulose graft copolymers with poly(γ-benzyl-L -glutamate) and poly(N⁵-2-hydroxyethyl-L -glutamine) (Cell-g-PBLG and Cell-g-PHEG) was examined in vivo blood tests. For this purpose, Cell-g-PBLG graft copolymers with PBLG contents ranging from 7 to 60 mol % were prepared by polymerizing N-carboxy-γ-benzyl-L-glutamate(γ-BLG NCA) using aminoethyl cellulose (AE-Cell) with degree of substitution of 0.05 as macroinitiator. Graft copolymerization was carried out under a variety of conditions at 20°C in dimethyl-sulfoxide. Monomer conversion higher than 60% were obtained for all the polymerization runs. The solubility tests revealed that all of the AE-Cell and the polypeptides formed were grafted. The Cell-g-PHEG graft copolymers were prepared by treating Cell-g-PBLG graft copolymers with 2-amino-1-ethanol. Characterization of these graft copolymers were carried out by IR spectroscopy, DSC, and water content measurement. Tests for blood compatibility, in vivo, were made by a method of peripheral vein indwelling suture which was developed by one of the authors. The coating of graft copolymers on the polyester suture was made by casting either from formic acid solution of LiCl/dimethylacetamide solutions using water as the regenerating medium, and the polymer-coated sutures were implanted into a jugular and femoral vein of a dog. The results showed that the graft copolymers examined have excellent antithrombogenic properties.     

Graft copolymerization of acrylic acid onto cellulose: Effects of pretreatments and crosslinking agent

The graft copolymerization of acrylic acid (AA) and 2‐acrylamido 2‐methylpropane sulfonic acid (AASO₃H) onto cellulose, in the presence or absence of crosslinking agent N,N′‐methylene bisacrylamide (NMBA), by using different concentrations of ceric ammonium nitrate (CAN) initiator in aqueous nitric acid solution at either 5 or 30°C was investigated. To investigate the effect of pretreatment of cellulose on the copolymerization, before some grafting reactions cellulose was pretreated with either 2 or 20 wt % NaOH solutions or heated in distilled water/aqueous nitric acid (2.5 × 10^?3 M) at 55°C. To determine how the excess of initiator affects the grafting and homopolymerization, separate reactions were carried out by removing the excess of ceric ions by filtration of the mixture of initiator solution and cellulose before the monomer addition. Extraction‐purified products were characterized by grafting percentage and equilibrium swelling capacity. Pretreatment of cellulose with NaOH solutions decreased the grafting percentage of copolymers. In the case of AA–AASO₃H mixtures, nonpretreated cellulose gave a higher grafting percentage than NaOH‐pretreated cellulose. Filtration also lowered the grafting of AA on the cellulose in the cases of pretreatment with either water or nitric acid. Copolymers with the highest grafting percentage (64.8%) and equilibrium swelling value (105 g H₂O/g copolymer) were obtained in grafting reactions carried out in the presence of NMBA at 5°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2267–2272, 2001     

Synthesis and characterization of N‐vinyl pyrrolidone and cellulosics based functional graft copolymers for use as metal ions and iodine sorbents

To develop cost effective and eco friendly polymeric materials for enrichment and separation technologies, 1‐vinyl‐2‐pyrrolidone (N‐VP) was graft copolymerized onto cellulose, extracted from pine needles. Optimum conditions have been evaluated for the grafting of N‐VP onto cellulose and at these conditions it was also grafted onto cellulose phosphate, hydroxypropyl cellulose, cyanoethyl cellulose, and deoxyhydrazino cellulose. At the optimum grafting conditions for N‐VP, it was also cografted with maleic anhydride. Kinetics of radiochemical graft copolymerization has been studied and evaluation of the polymerization and grafting parameters as percent grafting, percent grafting efficiency, rate of polymerization, homopolymerization, and graft copolymerization have been evaluated. Graft copolymers have been characterized by elemental analysis, FTIR, and swelling studies. An attempt has been made to study sorption of some metal ions such as Fe²⁺ and Cu²⁺ and iodine on select graft copolymers to investigate selectivity in metal ion sorption and iodine sorption as a function of structural aspects of the functionalized graft copolymers to find their end uses in separation and enrichment technologies. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 373–382, 2005     

Functionalization of poly(4‐vinyl pyridine) grafted cellulose by quaternization reactions and a study on the properties of postquaternized copolymers

Graft copolymers of 4‐vinyl pyridine (4‐VP) synthesized by using simultaneous gamma irradiation method were further functionalized by post polymer quaternization reactions at N: of the pyridine ring of the graft copolymers. Using the optimum grafting conditions reported earlier for the grafting of 4‐VP onto extracted cellulose, graft copolymer was synthesized in bulk and was further functionalized by quaternization with hexyl bromide (C₆H₁₃Br), benzyl chloride (C₆H₅CH₂Cl), n‐butyl bromide (C₄H₉Br), and maleic anhydride (MAnh). The quaternized polymers were studied for treatment of hardness of water, antibacterial action, emulsification properties, metal ion uptake and stability toward thermal degradation, and enzymatic and alkaline hydrolysis to evaluate the suitability of these polymers in harsh chemical, microbial, and thermal environments. The functionalized polymers were also characterized for surface morphology (SEM), elemental analysis and FTIR for investigations of structural aspects, and to obtain evidence for quaternization. The functionalized copolymers exhibit a range of properties that can be used in many fields of water purification technologies including antibacterial agents and ion exchangers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2454–2464, 2004     

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     

Polymers from renewable resources: Kinetics studies of the radiochemical graft copolymerization of styrene onto cellulose extracted from pine needles and the effect of some additives on the grafting parameters in an aqueous medium

In an attempt to develop an alternative to petro‐based polymers, we graft‐copolymerized cellulose isolated from the needles of Pinus roxburghii with styrene in a limited aqueous medium in air by simultaneous irradiation using gamma rays as the initiator. The optimum conditions for obtaining maximum grafting were determined as a function of monomer concentration, total dose of irradiation, and amount of water. Maximum percentage of grafting (P_g; 79.9) was obtained at a total dose of 1.152 × 10⁴ Gy with 1.325 × 10^?4 mol of styrene. The effect of methanol, LiNO₃, Cu(NO₃)₂, Mohr's salt, H₂SO₄, HNO₃, and AcOH on P_g was studied. All the additives were found to decrease graft yield, contrary to some reported studies. Total percentage conversion and rates of polymerization, grafting, and homopolymerization were evaluated. Evidence of grafting was provided by the characterization of cellulose and its graft copolymers by Fourier transform infrared spectroscopy, thermogravimetry, and observation of the swelling behavior in some solvents. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1490–1500, 2002     

Radiation-induced graft copolymerization of mixtures of styrene and n-butyl acrylate onto cellulose and cellulose triacetate

Mixtures of styrene and n-butyl acrylate of various compositions were grafted onto cellulose and cellulose triacetate fibers preirradiated with γ-rays at 0°C in air. Monomer reactivity ratios of the grafted copolymers were found to be different from those of the nongrafted copolymers or those of AIBN-initiated copolymers. The active species initiating the graft copolymerization were trapped radicals for cellulose and peroxides for cellulose triacetate. Kinetic investigations of the graft copolymerization of styrene onto preirradiated cellulose triacetate fibers were also carried out, and it was found that the kinetic scheme for radical polymerization is also applicable to graft copolymerization in a heterogeneous system.     

Grafting of dichlorodimethylsilane onto cellulose acetate as a model system in homogeneous media

Homogeneous graft copolymerization of dichlorodimethylsilane (DCDMS) onto cellulose acetate (CA) was carried out in acetone. The weight conversion, grafting percentage and grafting efficiency were determined as functions of the polymerization temperature and the concentrations of monomer and cellulose acetate. The IR and NMR data of the graft copolymers showed peaks characteristic of grafted chains. The order of the solvents used for increasing the grafting yield values was found as follows: cyclohexanone > ethyl acetate > dioxane, which is in accordance with their dielectric constants. Cellulose acetate previously oxidized by treatment with a mixture of oxalic acid and potassium dichromate when grafted with DCDMS gave low grafting yield values. The rate of copolymerization grafting of DCDMS onto CA was determined (R_p = 1.1 %min⁻¹). The activation energy of the reaction between DCDMS and CA was calculated (1.32 kJ mol⁻¹, 0.32 kcal mol⁻¹). The mechanism of graft copolymerization of DCDMS onto CA is discussed.     

Preparation and flocculation behavior of cellulose‐g‐PMOTAC copolymer

As a contribution to the wider use of biodegradable materials, this article reports the synthesis and testing of cationic polyelectrolyte cellulose derivatives for use as flocculation chemicals. Cellulose macroinitiator is synthesized in DMAc/LiCl solvent system by direct acylation of cellulose with 2‐bromoisobutyryl bromide. Cellulose‐graft‐poly(N,N‐dimethyl aminoethyl methacrylate) (cellulose‐g‐PDMAEMA) copolymers are prepared by copper‐mediated radical polymerization in homogeneous medium. Formation of the macroinitiator and graft copolymers is confirmed by ATR‐FTIR and ¹H NMR. Quaternization of the graft chains to poly(methacryloxyethyl trimethylammonium chloride) (PMOTAC) produces cellulose‐g‐PMOTAC, which performs similarly to a commercial product in flocculation of pulp and kaolin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40448.     

Liquid crystalline acrylic copolymers for high-solids enamel coatings

Carboxyl functional liquid crystalline (LC) acrylic copolymers were synthesized and were compared with carboxyl functional control copolymers of M?_n about 5000–15,000. Both types were crosslinked with a hexakismethoxymethyl melamine (HMMM) resin at 150°C, a temperature below the clearing points of the LC copolymers. Birefringent phases were visible in the crosslinked films made from LC polymers. FT-IR indicated the presence of unreacted COOH in all crosslinked materials. Unreacted COOH groups in crosslinked LC copolymers appeared only slightly higher than those in crosslinked amorphous copolymers. The potential utility of these LC copolymers as binders for thermosetting coatings was assessed. Variables studied were HMMM content, the length of PHBA grafts, T_g and M?_n of the acrylic copolymer backbone, and functionality. Optimum LC copolymers have low backbone T_g (<O°C) and low functionality (< 7.5 mol %). Cured films of such copolymers have both high hardness (> 35 KHN), high impact resistance (> 80 in. ib), excellent adhesion, and good solvent resistance.     

Properties and crystallization kinetics of poly(ether ether ketone)‐co‐poly(ether ether ketone ketone) block copolymers

A series of block copolymers composed of poly(ether ether ketone) (PEEK) and poly(ether ether ketone ketone) (PEEKK) components were prepared from their corresponding oligomers via a nucleophlilic aromatic substitution reaction. Various properties of the copolymers were investigated with differential scanning calorimetry (DSC) and a tensile testing machine. The results show that the copolymers exhibited no phase separation and that the relationship between the glass‐transition temperature (T_g) and the compositions of the copolymers approximately followed the formula T_g = T_g1X₁ + T_g2X₂, where T_g1 and T_g2 are the glass‐transition‐temperature values of PEEK and PEEKK, respectively, and X₁ and X₂ are the corresponding molar fractions of the PEEK and PEEKK segments in the copolymers, respectively. These copolymers showed good tensile properties. The crystallization kinetics of the copolymers were studied. The Avrami equation was used to describe the isothermal crystallization process. The nonisothermal crystallization was described by modified Avrami analysis by Jeziorny and by a combination of the Avrami and Ozawa equations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1652–1658, 2005     

Characterization and thermal stability of cellulose‐graft‐polyacryloniytrile prepared by using KMnO4/citric acid redox system

An effective condition of graft polymerization of acrylonitrile onto cellulose fiber in large volume of KMnO₄/citric acid aqueous solution was examined and the produced grafted copolymers were characterized by using SEM, NMR, FTIR, XRD, TGA, and DSC in comparison with component homopolymers. Graft yield, GY, obtained by simple weighting method was close to the value obtained by NMR analysis. Significant change of chemical structure in cellulose fiber, other than graft reaction, was not detected by NMR and FTIR measurements, whereas a decrease in the degree of crystallinity by the reaction was detected by XRD measurement. It was pointed out that thermograms for grafted samples resembles with that of cellulose at T < 370°C and become similar with that for polyacrylonitrile at T > 370°C and the mass of residue at 550°C is proportional to the content of polyacrylonitrile (GY) only. It is concluded that thermal decomposition of both polymers occurs almost independently in grafted polymers and thermal stability of cellulose fiber is not improved. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation,characterization, and properties of cellulose–polyacrylamide graft copolymers

Graft copolymers of acrylamide on cellulose materials (α‐cellulose 55.8%, DP 287.3) obtained from Terminalia superba wood meal and its carboxymethylated derivative (DS 0.438) were prepared using a ceric ion initiator and batch polymerization and modified batch polymerization processes. The extent of graft polymer formation was measured in graft level, grafting efficiency, molecular weight of grafted polymer chains, frequency of grafting as a function of the polymerization medium, and initiator and monomer concentrations. It was found that the modified batch polymerization process yielded greater graft polymer formation and that graft copolymerization in aqueous alcohol medium resulted in enhanced levels of grafting and formation of many short grafted polymer chains. Viscosity measurements in aqueous solutions of carboxymethyl cellulose‐g‐polyacrylamide copolymer samples showed that interpositioning of polyacrylamide chains markedly increased the specific viscosity and resistance to biodegradation of the graft copolymers. The flocculation characteristics of the graft copolymers were determined with kaolin suspension. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 913–923, 2003     

Core Cross-Linked Amphiphilic Star-Block Copolymers with (Meth)acrylic Acid Shells Prepared by Atom Transfer Radical Polymerization

Core cross-linked amphiphilic star-block copolymers were prepared by hydrolysis of the outer shell of star-block copolymers prepared using copper mediated atom transfer radical polymerization (ATRP). In an arm-first approach, linear poly(tert-butyl methacrylate) macroinitiators (PtBMA-Cl) were extended with styrene to yield PtBMA-b-PS-Cl and then cross-linked with divinylbenzene (DVB) in order to yield (PtBMA-b-PS)_arms-PDVB_core star-block copolymers. Then, PMAA-b-PS block and (PMAA-PS)_arms-PDVB_core star-block copolymers were obtained by hydrolysis of the PtBMA blocks in both linear and cross-linked copolymers, as confirmed by ¹H NMR analyses. The amphiphilic character of these copolymers was confirmed by solubilisation in water. Several factors affecting the polymer aggregation and solubility such as the length, the composition of the arms and the catalyst used were studied. An acrylate analogue, that is, (PAA-b-PS)_arms-PDVB_core, was also prepared for comparison purposes. Atomic force microscopy (AFM) and differential scanning calorimetry (DSC) were used to elucidate the morphology and the thermal behaviour of the star-block copolymers.