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A new strategy combing quantitative reactions and reversible-covalent chemistry is proposed for sequential synthesis of a series of sequence-controlled polymers with different sequences. Using a Michael addition reaction between acrylate and thiol, an aminolysis reaction of five-membered cyclic dithiocarbonate and a thiol substitution reaction of bromomaleimide and thiol, AB-, AB'C- and AB'CD-sequenced molecules are synthesized via AB, AB'C and AB'CD sequential monomer additions, respectively. These three molecules all have furan-protected maleimido group at one end, and the other end of AB-, AB'C- and AB'CD-sequenced molecules is amine, thiol and anthracene groups, respectively. Due to the fact that the furan-protected maleimido group can be efficiently transformed to maleimide group at high temperature via retro Diels-Alder reaction, AB-, AB'C- and AB'CD-sequenced molecules polymerize into sequence-controlled polymers with corresponding sequences at 120 °C. Through this strategy, the synthesis of molecular modules does not require separation and purification, and sequence-controlled polymers with specific sequence can be synthesized in a one-pot process via adding different monomers and adjusting reaction condition.

By combination of high trapping radical efficiency of thioketone with resonance of allylic radicals, a novel mediated agent, 1, 3, 3-triphenylprop-2-ene-1-thione (TPPT) has been successfully synthesized. 1H NMR method was used to trace the TPPT-mediated radical polymerization of butyl acrylate (BA) at 50 °C, we observed that the disappearance rates of BA, TPPT and initiator, dimethyl 2,2′-azobis (2-methylpropionate) (AIBME) have the following order: BA > AIBME > TPPT, monomer conversion increases gradually with proceeding of the polymerization and approximately 84% of conversion was obtained within 24 h of the polymerization. The molecular weights of the obtained PBA are not varied obviously with the conversion, but the molecular weight distributions are narrow. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) studies reveal three polymerization mechanisms. The TPPT can efficiently capture the growing PBA radicals to form PBA-TPPT• radicals, and this highly stable radicals are able to be cross-terminated by the growing PBA• radicals or primary radicals to form the dormant chains. Although the reversed reaction of reaction 1 is very slow, the extension polymerization of the PBA can undergo to form block copolymers. The molecular weight of the formed PBA is influenced by the feed molar ratio of BA/TPPT and TPPT/AIBME.

Polymerization-induced self-assembly (PISA) is an efficient and robust strategy to fabricate polymeric nano-objects. PISA enables us to prepare polymeric nano-objects in situ during the course of polymerization in concentrated solution (up to 50% w/w), making industrial production of polymeric assemblies in large-scale possible. In this work, reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of styrene (St) and N-methacryloxysuccinimide (NMAS) was conducted with poly(2-hydroxyethyl acrylate) (PHEA) as a macro-chain transfer agent (macro-CTA) in methanol. Compared with the PHEA-mediated alcoholic dispersion polymerization of St, RAFT dispersion copolymerization of St and NMAS promoted morphology transition of nano-objects to form higher order morphologies (such as worms and vesicles). Moreover, the introduction of NMAS units into the solvophobic blocks provided functional handles for post-PISA modification of the resultant nano-objects via the active ester-amine reaction. The reaction of 1,6-hexanediamine with NMAS units in P(St-co-NMAS) blocks was conducted to afford cross-linked nano-objects with robust structural stability.

Graft copolymers with pendant macrocycles were synthesized via “graft onto” method. First, cyclic polystyrene (PS) was achieved by the combination of atom transfer radical polymerization (ATRP) and Cu-catalyzed azide–alkyne cycloaddition (CuAAc), and then an alkynyl group was introduced to cyclic PS. Meanwhile, poly(3-azide-2-hydroxypropyl methacrylate) (PGMA-N 3 ) was synthesized by ATRP of glycidyl methacrylate (GMA) and successive ring-opening of pendant epoxide ring with NaN 3 . The graft copolymer was achieved by the following click reaction between PGMA-N 3 and alkynyl-containing cyclic PS. GPC and 1 H NMR were utilized to characterize the obtained graft copolymers, and a maximal grafting density of 20% was observed. Thermal behaviors of linear PS, cyclic PS and PGMA grafted with cyclic PS (PGMA-g-cPS) were investigated by differential scanning calorimeter (DSC), and T g of PGMA-g-cPS is higher than those of linear and cyclic PS.

Various morphologies including spherical micelles, nanowires and vesicles have been prepared by reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of styrene (St) in methanol using S-1-dodecyl-S -(α,α′-dimethyl-α″-acetic acid) trithiocarbonate (TC)-terminated poly(ethylene oxide) (PEO-TC) and 2,2′-azobis(isobutyronitrile) (AIBN) as chain transfer agent and initiator, respectively. GPC, 1H NMR, TEM and laser light scattering (LLS) were used to track the polymerization. The results showed that the block copolymers PEO-b-polystyrene (PEO-b-PS) were formed firstly in homogenous polymer solution, and then the spherical micelles were produced via polymerization-induced self-assembling. Continuous polymerization of the PS blocks induced the transition of spherical micelles into other morphologies. The polymerization-induced self-assembling and reorganization (PISR) were induced by chain length ratio increase of PS to PEO blocks. The concentration of St in methanol is also important factor to influence the formation of morphologies.

Hyperbranched poly(2-((bromobutyryl)oxy)ethyl acrylate) (HPBBEA) was grafted onto the exterior surface of mesoporous silica nanoparticles (MSNs) by surface-initiated self-condensing atom transfer radical vinyl polymerization (SCATRVP). The MSNs with ATRP initiator anchored on the exterior surface (MSN-Br) were prepared by the reaction of 5,6-dihydroxyhexyl-functionalized MSNs (MSN-OH) with α-bromoisobutyryl bromide. Afterwards, MSN-Br was utilized as initiator in the SCATRVP of inimer BBEA, resulting in core–shell nanoparticles with MSN core and HPBBEA shell (MSN-g-HPBBEA). The molecular weight of HPBBEA increased with the increasing ratio of BBEA to MSN-Br. In view of the high density of bromoester groups on the surface of HPBBEA shell, MSN-HPBBEA was used to initiate the successive polymerization of (2-dimethylamino-ethylmethacrylate) (DMAEMA), forming core–shell nanoparticles MSN-g-HPBBEA-g-PDMAEMA. The resultant products were characterized by FT-IR, NMR, HRTEM and thermogravimetric analysis (TGA), etc. The pH-responsive property of MSN-g-HPBBEA-g-PDMAEMA was characterized by measuring the hydrodynamics radius at different pH values, and this core–shell nanostructure may have potential applications in biomedicine and biotechnology.

The thin films of a symmetric crystalline-coil diblock copolymer of poly(L-lactic acid) and polystyrene (PLLA-b-PS) formed lamellae parallel to the substrate surface in melt. When annealed at temperatures well above the glass transition temperature of PLLA block (T-g(PLLA)), the PLLA chains started to crystallize, leading to reorientation of lamellae. Such reorientation behavior exhibited dependence on the correlation between the crystallization temperature (T-c), the glass transition temperature of PS (T-g(PS)), the peak melting point of PLLA crystals (T-m(PLLA)), and the end melting point of PLLA crystals (T-m,end(PLLA)). When annealed at (T-c =) 80 degrees C (T-c < T-g(PS) < T-ODT, order-disorder transition temperature), 123 degrees C (T-g(PS) < T-c < T-m(PLLA) < T-ODT). 165 degrees C (T-g(PS) < T-m(PLLA) < T-c < T-m,end(PLLA) < T-ODT), the parallel lamellae became perpendicular to the substrate surface, exclusively starting at the edge of surface relief patterns. Meanwhile, the corresponding lamellar spacing was significantly enhanced.

Dendritic–linear–dendritic triblock copolymers composed of linear polystyrene (PSt) and poly(amidoamine) dendrons have been successfully synthesized. Two bromines-terminated PSt with Mn = 13,000 was prepared by atom transfer radical polymerization (ATRP) using α,α′-dibromo-p-xylene as initiator. Then the terminal bromines at both ends of PSt chains were replaced by one imine group of piperazine (PZ), and further Michael addition reaction of terminal PZ with excess 1,3,5-triacryloylhexahydro-1,3,5-triazine (TT) produced the first generation (G1) of the triblock copolymer. Continuous growth of dendrons from G1.5 to G4 at the both ends of PSt chains was carried out by the iterative Michael addition reactions with excess PZ and following TT. The ABA triblock copolymers composed of the G1–G4 dendrons and the linear PSt were obtained. Structures of the triblock polymers were characterized by GPC and 1H NMR spectra. Thermal phase transitions of the polymers were studied by DSC measurements, and all of the copolymers displayed a glass transition temperature.

Hyperbranched poly(amido amine)s containing vinyl and hydroxyl groups were successfully synthesized via Michael addition polymerization of triacrylamide (TT) and 3-amino-1,2-propanediol (APD) with equal molar ratio in feed. 1H, 13C and HSQC NMR techniques were used to clarify the structure of hyperbranched polymers and polymerization mechanism. The Michael addition reaction of hyperbranched poly(1TT-1APD)s with primary amine-terminated poly(e-benzyloxycarbonyl- l -lysine)s [PLys(Z)] yielded a star-like hyperbranched polymers with poly(1TT-1APD) core and Plys(Z) shell. The Z groups in PLys(Z) were removed under acidolysis, and thus star-like hyperbranched polymers with hydroxyl groups inside and primary amine groups outside were obtained successfully.

The three generations dendrimer-like copolymers C(PSt(PLLA(PSt–PNAS)2)2)3 and C(PSt(PLLA(PSt–PNAS)2)2)4 have been successfully synthesized by combination of ATRP and ROP. Diethanol amine and 2,2-bis(methylene-2-bromoisobutyrate) propionyl chloride (BMBIBPC) were used as divergent reagents, respectively, before preparations of the second and the third generations. The resultant polymers were characterized by GPC and 1H NMR. Then the outermost PSt–PNAS in the dendrimer-like copolymers was cross-linked via substitution reaction of NAS with ethylene diamine, and at the same time, the PLLA segments in the second generation were decomposed in dilute THF or CHCl3 solution, forming hollow particles. The resultant morphologies were characterized by SEM and DLS methods, and spherical particles with various sizes were observed. The hollow particles may have potential applications in catalysis and bioengineering.

Novel amphiphilic block copolymers, poly(ethylene oxide)- b -poly( p -nitrophenyl methacrylate) (PEO- b -PNPMA) with controlled molecular weights and narrow molecular weight distribution were successively synthesized by ATRP of NPMA using PEO–Br as initiator. Self-assembling of the diblock copolymer PEO 113 - b -PNPMA 28 in the different solvent mixtures yielded various morphologies of star micelle-like aggregates, such as spheres, vesicles, cauliflower-like aggregates and rod-like aggregates, which are determined by the nature of the common solvents and the selective solvents. Thus the critical selective solvent contents and the solvent contents in PNPMA-rich phase were measured, and they have the following order: ethanol > methanol > water, and THF > CH 3 NO 2 > DMSO. The probable self-assembling mechanism is discussed. This method is convenient for preparation of multiple morphological star micelle-like aggregates in solution, especially from the amphiphilic block copolymers with relatively longer block shell.

Reversible addition-fragmentation chain transfer (RAFT) functionalities were anchored to the exterior surface of mesoporous silica nanoparticles (MSNs) without changing the mesoporous structure, RAFT polymerization of styrene was subsequently conducted to graft polystyrene (PSt) onto the exterior surface of MSNs, forming a novel core–shell nanostructure with a mesoporous core and a polymer nanoshell. Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) were used to characterize the produced mesoporous core–shell nanostructure, the results showed that the thickness of the nanoshell increased with the increasing time of polymerization.

Functionalized star polymers with tetraaniline on their surface have been successfully prepared by substitution reaction of N -succinimidyl-terminated star polymers with tetraaniline. A novel functional RAFT agent bearing N -succinimidyl group was used in the RAFT polymerization of styrene, and N -succinimidyl groups-terminated polystyrenes with narrow molecular weight distribution were obtained. The star polymers with reactive N -succinimidyl groups on their surface were synthesized via RAFT polymerization of DVB. Polymerization mechanism study by gel permeation chromatography displayed that complete disappearance of linear polymers in the products is difficult. The N -succinimidyl-terminated PSt, polymer stars with surface N -succinimidyl groups and the PSt- b -tetraaniline stars were characterized by 1 H NMR spectroscopy, FT-IR and GPC.

Reversible addition–fragmentation chain transfer (RAFT) polymerization was used to graft polystyrene (PS) onto silica nanoparticles. A novel route was used to prepare the RAFT agent, 2-butyric acid dithiobenzoate (BDB) by substitution of dithiobenzoate magnesium bromide with sodium 2-bromobutyrate under alkali condition in aqueous solution. Epoxy groups were covalently attached to silica nanoparticles by condensation reaction of 3-glycidyloxypropyltrimethoxysilane (GPS) with the hydroxyl on the silica particle surface. RAFT agent functionalized nanoparticles were produced by ring-open reaction of the epoxy group with the carboxyl group of BDB. Then, PS chains with controlled molecular weights and narrow polydispersities (less than 1.1) were grown from the RAFT agent anchored nanoparticle surface. FT-IR, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) results showed that PS chains grew from silica particles by surface RAFT polymerization.

The triblock copolymers, poly(styrene- b -isoprene- b - e -caprolactone)s (PS- b -PI- b -PCL) have been synthesized successfully by combination of anionic polymerization and ring-opening polymerization. Diblock copolymer capped with hydroxyl group, PS- b -PI-OH was synthesized by sequential anionic polymerization of styrene and isoprene and following end-capping reaction of EO, and then it was used as macro initiator in the ring-opening polymerization of CL. The results of DSC and WAXD show big effect of amorphous PS- b -PI on the thermal behaviors of PCL block in the triblock copolymers and the lower degree of crystalline in the triblock copolymer with higher molecular weight of PS- b -PI was observed. The real-time observation on the polarized optical microscopy shows the spherulite growth rates of PCL 27 , PCL 328 and PS- b -PI- b -PCL 344 are 0.71, 0.46 and 0.07 μm s −1 , respectively. The atomic force microscopy (AFM) images of the PS 90 - b -PI 66 - b -PCL 28 show the columns morphology formed by it’s self-assembling.

Well-ordered nanostructured polymeric supramolecular thin films were fabricated from the supramolecular assembly of poly(styrene-block-4-vinylpyridine) (PS-b-P4VP)(H+) and poly(methyl methacrylate)-dibenzo-18-crown-6-poly(methyl methacrylate) (PMCMA). A depression Of cylindrical nanodomains was formed by the block of P4VP(H+) and PMCMA associates surrounded by PS. The repulsive force aroused from the incompatibility between the block of P4VP(H+) and PMCMA was varied through changing the molecule weight (M-w) of PMCMA, the volume fraction of the block of P4VP(H+), and annealing the film at high temperature. Increasing the repulsive force led to a change of overall morphology from ordered nanoporous to featureless structures. The effects of solvent nature and evaporation rate on the film morphology were also investigated. Further evolution of surface morphologies from nanoporous to featureless to nanoporous structures was observed upon exposure to carbon bisulfide vapors for different treatment periods. The wettability of the film surface was changed from hydrophilicity to hydrophobicity due to the changes of the film surface microscopic composition.

Functionalized star polymers with tetraaniline on their surface have been successfully prepared by substitution reaction of N-succinimidyl-terminated star polymers with tetraaniline. A novel functional initiator bearing N-succinimidyl group was used in atom transfer radical polymerization (ATRP) of styrene, and polystyrenes (PSts) having N-succinimidyl groups with narrow molecular weight distribution were obtained. The star polymers with reactive N-succinimidyl groups on their surface were synthesized by ATRP of divinylbenzene (DVB). The N-succinimidyl-terminated PSt, polymer stars with surface N-succinimidyl groups and the PSt-b-tetraaniline stars were characterized by 1H NMR spectroscopy, FT-IR and gel permeation chromatography.

Dendrimer-like copolymers with two and three generations, (polystyrene)3-b-(poly( l -lactide))6 (PSt3-b-PLLA6) and PSt3-b-PLLA6-b-PSt12 have been successfully prepared using core-first method. The first step of this synthesis is the preparation of three-armed PSt by atom transfer radical polymerization (ATRP) of St using 1,1,1-tri(methylene-α-bromoisobutyryl)propane as initiator. Terminal divergence of the polymers obtained was achieved by the reaction of terminal bromines with branching agent, 2,2-dimethyl-1,3-dioxolane-4-methanol. After deprotection, the polymer with six terminal hydroxyl groups was used in the ring-opening polymerization of LLA. The dendrimer-like copolymer with PLLA as a second generation diverged continuously by the reaction of 6 terminal hydroxyl groups with branching agent, 2,2-bis(methylene-α-bromoisobutyryl)propionyl chloride. The resultant polymer with 12 terminal bromines was used as macroinitiator in the ATRP of St to produce the target dendrimer-like copolymer, PSt3-b-PLLA6-b-PSt12. The structures of polymers obtained from each step were confirmed by their 1H NMR spectra and GPC measurements. DSC results show one T g PS = 102 ° C for the three-armed PSt, T g PLLA = 53 ° C , T c PLLA = 123 ° C and T m PLLA = 159 ° C for the dendrimer-like copolymer with two generations, C(PSt(PLLA)2)3, and T g PLLA = 53 ° C , T c PLLA = 114 ° C and T m PLLA = 166 ° C for the copolymer with three generations, C(PSt(PLLA(PSt)2)2)3.

Linear pH-sensitive poly(amido amine)s were synthesized via Michael addition polymerization of N-aminoethyl piperazine (AEPZ) or 4-aminomethyl piperidine (AMPD) with 1,12-dodecylene diacrylamide (DDA). Successive Michael addition reaction of acryl-terminated poly(ethylene oxide) (A-PEO) with the secondary amine of linear poly(DDA–AEPZ) that has one secondary amine in every repeating unit afforded PEO-grafted poly(amido amine). Variation of grafting degree could be obtained conveniently via tuning the feed molar ratio of acryl/secondary amine. When this ratio equals to 1.2, all the secondary amines on the backbone of poly(DDA–AEPZ) (or poly(DDA–AMPD)) were consumed and the comb-shaped polymers were formed. The amphiphilic comb-shaped poly(DDA–AEPZ)-g-PEO was molecularly dissolved in water at pH 2.0 (w/v=0.25%), and micelles were formed when pH value of aqueous solution was adjusted to 6.5. 1H NMR data verify the formation of micelles due to the disappearance of signals attributed to poly(DDA–AEPZ). The formation of micelles can be confirmed further by TEM photos, they show that all the particles are approximately spherical and their number-average diameter is around 95 nm.

A new method to graft a large number of long polymer chains or small functional molecules onto multi-walled carbon nanotubes (MWNTs) indirectly is reported. First, MWNTs were slightly functionalized by reversible addition–fragmentation chain transfer (RAFT) copolymerization of styrene and maleic anhydride using the dithioester groups attached to MWNTs as RAFT agents. The highly reactive maleic anhydride groups could further react with a large number of long polymer chains or small functional molecules with hydroxyl or amino group easily. The resulted MWNTs have good solubility in organic solvents and water; the perfect structure of MWNTs is altered very little from the information of Raman spectra.

Two dendritic reversible addition–fragmentation transfer (RAFT) agents with 8 and 16 terminal dithiobenzoate (DTB) groups on the surface of poly(propylene imine) (PPI) dendrimers (generation 2.0 and 3.0, respectively) were successively prepared, and they were used in the RAFT polymerization of N -isopropylacrylamide (NIPAAM). The polymerization kinetics was confirmed to pseudo-first-order behavior. The 1 H NMR and GPC analyses show that the dendrimer-star den (NIPAAM) x ( x = 8 or 16) prepared by RAFT method has well-defined structure, controlled molecular weight and low polydispersities (PDI

The amphiphilic π-shaped copolymers with narrow molecular weight distribution ( M w / M n = 1.04–1.09) based on polystyrene (PSt) and poly(ethylene glycol) have been synthesized successfully. The reversible addition-fragmentation transfer (RAFT) polymerization of St in the presence of dibenzyl trithiocarbonate and N , N ′-azobis(isobutyronitrile) (AIBN) yielded macro RAFT agent PSt–SC( S)S–PSt, subsequent reaction with excess maleic anhydride (MAh) at 80 °C in tetrahydrofuran afforded the PSt–MAh–SC( S)S–MAh–PSt. It was used as RAFT agent in the RAFT polymerization of St, and finally the amphiphilic π-shaped copolymers were obtained by the reaction of MAh with hydroxyl-terminated poly(ethylene glycol methyl ether) at 90 °C for 48 h. Their structures were confirmed by FT-IR and 1 H NMR spectra, and their molecular weight and molecular weight distribution were measured by gel permeation chromatography.

The free-radical polymerizations of methyl acrylate (MA) have been systematically studied under 60 Co γ-ray irradiation using benzyl propane(dithioate) ( a ), benzyl phenylethane(dithioate) ( b ), benzyl benzenecarbodithioate ( c ), benzyl 4-cyanobenzenecarbodithioate ( d ) and benzyl 4-methoxybenzenecarbodithioate ( e ) as control agents. The results indicate that Z-group of dithioester plays an important role in the polymerization behavior. When Z-group is alkyl or alkyl derivative, in the case of dithioester a and b , the polymerizations reveal quite good living characteristics except for a similar inhibition period of about 40 min, which may be attributed to the lower propagation rate coefficients during the initialization period. However, for dithioesters c , d and e , aryl as Z-group, the polymerizations show very strong inhibitions in the processes. The strong inhibition may be associated with the formation of probable 3 or 4-arm structure compounds. It is worth noting that it is the first report for dithioester a to be used as control agent in ‘controlled/living’ free radical polymerization under γ-ray irradiation.

A novel trithiocarbonate, S,S′-bis(1-(((5-ethyl-2,2-dimethyl-1,3-dioxane-5-yl)methoxy)carbonyl)propyl) trithiocarbonate (CTA-H), was synthesized in the presence of the anion-exchange resin with OH − form. And then it was used as the chain transfer agent in RAFT polymerizations of styrene (St), the polymers with controllable molecular weights and narrow molecular weight distributions were synthesized. After the terminal acetonide groups was deprotected in the presence of a cation-exchange resin with H + form, the polystyrene (PSt) with two hydroxyl groups in both chain ends was easily afforded. Then it was used as macro initiator in the cation ring open polymerization (CROP) of 1,3-dioxepane (DOP), and the well-defined H-shaped block copolymers, (PDOP) 2 PSt(PDOP) 2 , were successfully prepared. The H-shaped structure was characterized by its IR, GPC and 1 H NMR spectra, and also those of the hydrolysis products.

Hexa-armed star block copolymers, s-[poly(l-lactide)-b-poly(styrene-co-N-acryloxysuccinimide)]6 (s-[PLLA-b-poly(St-co-NAS)]6) with triphenylene core have been successively prepared by the combination of ring-opening polymerization and atom transfer radical copolymerization, and they were used in the self-assembly in tetrahydrofuran, and the micelles with triphenylene core and PLLA as inner layer as well as poly(St-co-NAS) as shell were formed. After shell was cross-linked, PLLA was hydrolyzed in aqueous NaOH solution, the hollow spheres were formed. The structures, molecular weight and polydispersity index of the polymers were characterized by their 1H NMR and FT-IR spectra, as well as GPC. Their morphologies were studied by TEM. The influence factors on the formation of various morphologies are under investigation.

Crown ether-centered two-armed polymers, i.e., polystyrene-dibenzo-18-crown-6-polystyrene (PSCS) and poly(methyl methacrylate)-dibenzo-18-crown-6-poly(methyl methacrylate) (PMCM), were designed to self-assemble in a proposed manner directed by the specific affinity between the polar crown ether rings. When spin coated onto a silicon wafer surface, macroporous films were obtained. In contrast, the proposed assemblies were strongly adsorbed on a highly polar mica surface, looking like porous islands near the spin center. At areas far from the spin center, these islands slipped to form terrace islands under the huge shear by the centrifugal force. The formation of the porous islands and terrace islands provide further evidence to the proposed assembling of the two-armed polymers.

A four probe method was used to measure the electrical conductivities of poly(styrene-co-acrylonitrile)/expanded graphite composites. The composites showed excellent electrical conductivities in both a- and c-axes. The different effects of temperature and the applied current on the conductivities in a-axis and in c-axis were observed. It was found that the conductive behaviors of the composite were different from those of semiconductor and carbon black loaded polymer composites. All these differences and excellent conductivity were considered to be related to the structure of the composites.

Comb-shaped graft copolymers with poly(methyl acrylate) as a handle were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP) techniques in three steps. First, copolymers of poly(styrene-co-chloromethyl styrene), poly(St-co-CMS), were prepared by RAFT copolymerization of St and CMS using 1-(ethoxycarbonyl)prop-1-yl dithiobenzoate (EPDTB) as RAFT agent. Second, the polymerization of MA using poly(St-co-CMS)-SC(S)Ph as macromolecular chain transfer agent produced block copolymer poly(St-co-CMS)-b-PMA. Third, cationic ring-opening polymerization of THF was performed using poly(St-co-CMS)-b-PMA/AgClO4 as initiating system to produce comb-shaped copolymers. The structures of the poly(St-co-CMS), poly(St-co-CMS)-b-PMA and final comb-shaped copolymers were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC).

An amphiphilic rod-coil ABC triblock copolymers using rigid oligo( para -phenyleneethynylene) (OPE) as the middle rod segment, poly(ethylene oxide)- block -oligo( para -phenyleneethynylene)- block -polystyrene (PEO- b -OPE- b -PS), was designed and successfully synthesized. In the synthetic route, a kind of macroinitiator, PEO- b -OPE-Br was achieved by stepwise coupling of iodo-terminated poly(ethylene oxide) and oligo( para -phenyleneethynylene) with amino end group, capping with 2-bromopropionyl bromide. Subsequently, from this macroinitiator atom transfer radical polymerization (ATRP) of styrene was performed to obtain PEO- b -OPE- b -PS. The resulting copolymers were characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). All these novel copolymers were affirmed to have well-defined structures and narrow molecular weight distributions.

The polymerizations of methyl acrylate have been studied under thermal condition using benzyl 9 H -carbazole-9-carbodithioate (BCCDT) as control agent. The obtained polymers were characterized by gel permeation chromatography (GPC), 1 H nuclear magnetic resonance ( 1 H NMR) and MALDI-TOF mass spectra. The results at 60 °C show that the molecular weight of the polymer increases linearly with monomer conversion, the molecular weight distribution is fairly narrow (even inferior to 1.10), and there exists a linear relationship between ln ([ M ] 0 /[ M ]) and polymerization time. It is worthy of being noticed that the narrow polydispersities are comparable with those from living anionic polymerization. All of the evidences indicate that the polymerization is a good ‘living’ process. When the experiment is carried out at higher temperature, the polymerization rate is markedly faster with controlled polymerization characters except for a relatively broader polydispersity. The good control for free radical polymerization may be correlated with the large conjugation structure of carbazyl of BCCDT.

With the aim to get a clear understanding of this category of polymerizations, the Michael addition polymerizations of trifunctional amines, i.e. 4-aminomethyl piperidine (AMPD), N-methyl ethylenediamine (MEDA), and 1-(2-aminoethyl) piperazine (AEPZ), with an equimolar diacrylamide, N,N′-methylene diacrylamide (MDA), were investigated. Similar to the polymerizations of these amines with an equimolar diacrylate, novel linear poly(amido amine)s containing secondary and tertiary amines in the backbones are obtained from these polymerizations as reflected by 13C NMR (INVGATE). In situ monitoring the polymerization processes using NMR shows that the reactivity sequence of three types amines in the trifunctional amines is 2° amine (original)>1° amine≫2° amine (formed), and the 2° amine (formed) is kept out of the reaction. But these results are different from those reported for the polymerizations of the similar amines with an equimolar divinyl sulfone and some diacrylates. The molecular weights and properties of poly(amindo amine)s obtained were characterized by GPC, DSC and TGA, respectively.

Star polymers based on styrene/divinyl benzene (St/DVB) and PSt- b -poly( N -isopropyl acrylamide) (NIPAAM)/DVB have been successively prepared by ‘arm-first’ method via reversible addition-fragmentation chain transfer (RAFT) polymerization. The linear macro RAFT agent PSt-SC(S)Ph was prepared by RAFT polymerization of St using benzyl dithiobenzoate and AIBN as RAFT agent and initiator. Successive RAFT polymerization of NIPAAM with PSt-SC(S)Ph as macro RAFT agent to afford diblock copolymer, PSt-b-PNIPAAM-SC(S)Ph. The coupling reactions of PSt-SC(S)Ph or PSt-b-PNIPAAM-SC(S)Ph in the presence of DVB produced the star copolymers, C(PSt) n or C(PSt-b-PNIPAAM) n . The molar ratio of DVB/PSt-SC(S)Ph and polymerization time influenced the yields, molecular weight and distribution of the star-shaped polymers, which was characterized by 1 H NMR and IR spectra, GPC measurements as well as DLS.

Highly ordered honeycomb-like macroporous films were obtained via self-assembly of a two-armed polymer with a crown ether core under controlled conditions. A possible mechanism is speculated, primarily based on the strong affinity between the crown ether cores. The pore size and arrangement are sensitive to the solvent evaporation rate and the solution concentration. Upon spontaneous drying, the pore diameter (D) depends on the concentration (c) by a relation of D=518c(-0.610).

Poly(ethylene oxide) methyl ether/polystyrene/poly( l -lactide) (MPEO/PSt/PLLA) ABC miktoarm star copolymers were synthesized by combination of reversible addition–fragmentation transfer (RAFT) polymerization and ring-opening polymerization (ROP) using bifunctional macro-transfer agent, MPEO with two terminal dithiobenzoate and hydroxyl groups. It was prepared by reaction of MPEO with maleic anhydride (MAh), subsequently reacted with dithiobenzoic acid and ethylene oxide. RAFT polymerization of St at 110 °C yielded block copolymer, MPEO-b-PSt [(MPEO)(PSt)CH2OH], and then it was used to initiate the polymerization of l -lactide in the presence of Sn(OCt)2 at 115 °C to produce ABC miktoarm star polymers, s-[(MPEO)(PSt)(PLLA)]. The structures of products obtained at each synthetic step were confirmed by NMR and gel permeation chromatography data.

A novel reversible addition–fragmentation chain transfer (RAFT) agent, S,S′-bis(2-hydroxylethyl-2′-butyrate)trithiocarbonate (BHEBT), was first successfully synthesized in the presence of an anion-exchange resin with OH− form, and then it was used as chain transfer agent in RAFT polymerizations of styrene or methyl acrylate, the dihydroxyl-terminated polymers with controlled molecular weights and narrow molecular weight distributions were produced, which was confirmed by GPC, 1H NMR spectra and kinetic analysis. Furthermore, these obtained telechelic polymers with trithiocarbonate group in the middle of the chains were used as macro chain transfer agents in the further RAFT polymerizations, and well-defined telechelic dihydroxyl-terminated triblock copolymers have been prepared successively. The structures were confirmed by their IR and 1H NMR spectra.

We report a novel method to prepare graft copolymers of PS-g-PEGM with controlled backbone length, grafting sites and spacing length. This method involves three steps: first step, styrene was controlled to insert into the main chain of polytrithiocarbonate at the trithiocarbonate sites, the experimental results show that not only the chain length of the backbone, but also the length of polystyrene (PS) space chain between neighboring trithiocarbonate units can be well-controlled; second step, ‘grafting points’ maleic anhydride units were inserted into the backbone chain between St unit and trithiocarbonate unit; third step, poly(ethylene glycol methyl ether) (PEGM) chains were grafted onto the main chain by esterification reaction of maleic anhydride with PEGM to form graft copolymers of PS-g-PEGM with controlled backbone length, spacing length and well-defined grafting sites.

A new graphite/polystyrene composite was produced with cationic grafting polymerization of styrene initiated by CO+ClO−4 group on the surface of expanded graphite (EG). The structures of EG and the graphite/polystyrene composite were studied with SEM and optical micrograph. The spectra of XRD and IR were used not only for confirming whether the polymerization reaction took place, but also for determining whether the polystyrene in the composite covered the surface of EG particles or intercalated into EG particles. The electrical conductivity, thermal phase transitions and mechanical properties were also discussed.

Introducing isocyanate (NCO) groups onto the surface of expanded graphite (EG) was achieved by treatment of the EG with excess toluene-2,4-diisocyanate in dimethyl sulfoxide (DMSO). The reaction of NCO group on the EG with the hydroxyl group in the poly(ethylene oxide) methyl ether (MPEO) to yield MPEO-grafted EG was carried out for modifying the surface properties of graphite. The influence factors, such as reaction time, temperature and the ratio of the reactants, on the grafting reaction and grafting ratio were investigated.

Monte Carlo simulations were used to investigate the compatibilizing effects of diblock copolymers in A/B/A–B diblock copolymer ternary blends and triblock copolymers in A/B/triblock copolymer ternary blends, respectively. The volume fraction of homopolymer A was 19% and was the dispersed phase. The simulation results show that diblock copolymers with longer A-blocks are more efficient as compatibilizers, and symmetric triblock copolymers with a shorter middle block length are easily able to bridge each other through the association of the end blocks. This kind of triblock copolymers have relatively high ability to retard phase separation as compatibilizers.

Poly(styrene- co -acrylonitrile)/expanded graphite composite sheets with very low in-plane (8.5 × 10 −3 Ω cm) and through-thickness (1.2 × 10 −2 Ω cm) electrical resistivities have been prepared. The expanded graphite was made by oxidation of natural graphite flakes, followed by thermal expansion at 600 °C. Microscopic results disclosed that the expanded graphite has a legume-like structure, and each “legume” has a honeycomb sub-structure with many diamond-shaped pores. After soaking the expanded graphite with styrene and acrylonitrile monomers, the polymer/expanded graphite composite granules were obtained by in situ polymerization of the monomers inside the pores at 80 °C. The functional groups and microstructures of the oxidized graphite, expanded graphite and composites in the forms of particles or sheets were carefully characterized using various techniques, including X-ray powder diffraction, thermogravimetry, optical and electron microscopy. It was found that the honeycomb sub-structure survived after hot-pressing, resulting in a graphite network penetrating through the entire composite body, which produces a composite with excellent electrical conductivity.

Monte Carlo method was applied to simulate self-condensing vinyl polymerization (SCVP) in the presence of multifunctional initiator with unequal reactive rate constants. Simulations showed that, with the increase of reactivity of multifunctional initiator, the molecular weight distribution decreases, the fraction of multi-armed hyperbranched polymers increases, and the best reactivity ratio of multifunctional initiator to inimor is 10/1; the reactivity difference of two active sites in inimer has strong effects on the molecular weight distribution and degree of branching. The branch degree and fraction of branch-points depend on both the conversion of double bonds and reactivity difference of two active centers in inimer, and have no relation with the adding of multifunctional initiator. The density distribution of degree of branching further shows common self-similarity in SCVP.

Poly(4-vinylpyridine) (P4VP) and block copolymer, poly(4-vinylpyridine–b-styrene) (P4VP-b-PSt) were prepared by atom transfer radical polymerization (ATRP) using 1-phenylethyl chloride as initiator, CuCl and 5,5,7,12,12,14–hexamethyl-1,4,8,11-tetraazamacrocyclotetradecane (Me6[14]aneN4) as catalyst and ligand. The polymerization of 4VP was carried out in 2-propanol at 40 °C. GPC and NMR studies show that the plot of ln([4VP]0/[4VP]) against the reaction time is linear, and the molecular weight of the resulting P4VP increased linearly with the conversion. Within 3 h, the conversion can reach almost 90%. P4VP-b-PSt amphiphilic block copolymer with low polydispersity index (Mw/Mn ≈ 1.2) is also obtained by ATRP of St in DMF at 110 °C using P4VP–Cl as macroinitiator, CuCl/ Me6[14]aneN4 as catalyst.

Block copolymers, poly(LLA- b -St)s and triblock copolymes, poly(LLA- b -St- b -MMA)s have been synthesized by the combination of the atom transfer radical polymerization (ATRP) with ring-opening polymerization (ROP) using bifunctional initiator β-hydroxylethyl α-bromoisobutyrate (HEBIB) without intermediate function transformation. The molecular weight (MW) and the molecular weight distribution (MWD) can be controlled. The structures of the copolymers were confirmed by 1 H NMR spectroscopy and GPC.

It is the first report on the atom transfer radical ring-opening copolymerizations of unsaturated cyclic acetal: 4,7-dimethyl-2-methylene-1,3-dioxepane (DMMDO) with conventional vinyl monomers, styrene (St), acrylonitrile (AN) and methyl acrylate (MA) in the presence of ethyl α-bromobutyrate as initiator and CuBr/2,2′-bipyridyl as catalyst/ligand at 110 °C. 1H, 13C NMR and IR data show that the copolymerizations of DMMDO with St (or AN or MA) yield the copolymers, poly(DMMDO-co-St) [or poly(DMMDO-co-AN) or poly(DMMDO-co-MA)] with narrow molecular weight distribution, and low content of DMMDO in the copolymers for electron-donor St, higher contents of DMMDO for electron-acceptor AN or MA are observed.

Polystyrene-block-poly(5,6-benzo-2-methylene-1,3-dioxepane) (PSt-b-PBMDO), poly(methyl methacrylate)-block-PBMDO (PMMA-b-PBMDO) and poly(methyl acrylate)-block-PBMDO (PMA-b-PBMDO) were synthesized by two-step atom transfer radical polymerization (ATRP) of conventional vinyl monomers, then BMDO. First, the polymerization of St, or MMA, or MA was realized by ATRP with ethyl α-bromobutyrate (EBrB) as initiator in conjunction with CuBr and 2,2′-bipyridine (bpy). After isolation, polymers with terminal bromine, PSt-Br, PMMA-Br and PMA-Br, were obtained. Second, the ATRP of BMDO was performed by using macroinitiator, PSt-Br (or PMMA-Br, PMA-Br) in the presence of CuBr/bpy. The structures of block copolymers were characterized by 1 H NMR spectra. Molecular weight and polydispersity index were determined on gel permeation chromatograph. Among the block copolymers obtained, PMA-b-PBMDO shows the most narrow molecular weight distribution.

The copolymerization of styrene (St) with maleic anhydride (MAh) performed at 22 °C in the presence of dibenzyl trithiocarbonate exhibits controlled nature evidenced by: narrow molecular weight distribution, controlled molecular weight and first-order polymerization kinetics. The composition analysis of the copolymers obtained by 13 C NMR spectra shows the molar fraction of St in obtained copolymers is almost equal to 0.5 throughout the copolymerization. The sequence structure of the copolymer was obtained from DEPT experiments by recording the spectra at π/4 and 3π/4, and then combining them together, the results showed that the copolymers obtained possessed well-defined alternating structure. The experiment shows that charge-transfer-complex formed from St and MAh participates in both initiation and chain growth throughout the copolymerization.

Two functional crown ether initiator, bis[4′-(2-bromobutyryl)]dibenzo-18-crown-6 (BBDC) was synthesized through the condensation of dibenzo-18-crown-6 with 2-bromobutyric acid in the presence of polyphosphoric acid. Atom transfer radical polymerizations of styrene (St), methyl acrylate, methyl methacrylate and butyl acrylate were carried out in bulk to produce the polymers with well-controlled molecular weights and narrow molecular weight distributions (1.12–1.32). Based on 1H NMR results, both the two bromides of BBDC initiated the polymerizations. The well-defined two-armed polymers were self-assemblized in the presence of potassium cations. Their morphologies of the film obtained were studied by atomic force microscopy with tapping mode.

Novel narrow distributed nanospheres with polystyrene shells and cross-linked poly(methacrylamide) (polyMMA) cores were fabricated. The cross-linking of the poly(p-nitrophenyl methacrylate) (polyNPMA) cores of micelles, formed by the self-assembly of well-defined block copolymer (poly(styrene-b-p-nitrophenyl methacrylate) (poly(St-b-NPMA))) in chloroform, was realized in the solutions directly through the reaction with ethylenediamine instead of in films as in other cases reported [3] , [8] , [9] , [10] , [11] . Further substitution of p-nitrophenol units with ammonia produced polyMMA cores. Dynamic light scattering was used to monitor the self-assembly process of poly(St-b-NPMA) in chloroform, the effects of the cross-linking and amino-substitution of the polyNPMA cores on the morphologies of the micelles, meanwhile, the changes in the chemical structures were verified by FTIR.

A series of hyperbranched polyacrylates were synthesized by self-condensing vinyl polymerization (SCVP) of 2-[(2-bromobutyryl)oxy]ethyl acrylate (BBEA). A tetrafunctional atom transfer radical polymerization (ATRP) initiator (THABI) capped with bromoisobutyrate, which has higher reactivity than the initiating site of monomer, was used as core-forming molecules. The structure and properties of the obtained polymers were characterized by NMR and SEC/RALLS/DV/RI. The effect of the tetrafunctional initiator on molecular weight and molecular weight distribution of polymers was studied.

A series of hyperbranched polymers were synthesized in high yield by self-condensing vinyl polymerization (SCVP) of 2-[(2-bromobutyryl)oxy]ethyl methacrylate (BBEM) in the presence of an ATRP initiator: THABP (a tetrafunctional initiator)/CuBr/bpy. The structure and properties of the polymers obtained were characterized by NMR and SEC/RALLS/DV/RI. The effect of the tetrafunctional initiator on degree of branching (DB), molecular weight and molecular weight distribution of polymers was studied.