A straightforward approach was employed to synthesize methylene‐bridged poly(hetero aromatic)s ba... more A straightforward approach was employed to synthesize methylene‐bridged poly(hetero aromatic)s based on furan, pyrrole, thiophene, and thiophene derivatives. The process involved an electrophilic aromatic substitution reaction facilitated by a visible light‐initiated system consisting of manganese decacarbonyl and an iodonium salt. The approach mainly relies on the formation of halomethylium cation, the attack of this cation to heteroaromatic, regeneration of methylium cation on the heteroaromatic, and reactivity differences between halomethylium and heteroaromatic methylium cations for successful polymerizations. This innovative synthetic strategy led to the formation of polymers with relatively high molecular weights as the stoichiometric imbalance between the comonomers increased. Accordingly, these newly obtained polymers exhibited remarkable fluorescence properties, even at excitation wavelengths as low as 330 nm. Moreover, by harnessing the halogens at chain ends of homopolyme...
A novel method based on light‐induced fabrication of a poly (3,4‐ethylenedioxythiophene)‐polycapr... more A novel method based on light‐induced fabrication of a poly (3,4‐ethylenedioxythiophene)‐polycaprolactone (PEDOT‐PCL) scaffold using phenacyl bromide (PAB) as a single‐component photoinitiator is presented. HBr released from the step‐growth polymerization of EDOT is utilized as an in situ catalyst for the chain‐growth polymerization of ε‐caprolactone. Detailed investigations disclose the formation of a self‐assembled nanoporous electroconductive scaffold (1.2 mS cm−1). Fluorescence emission spectra of the fabricated scaffold exhibit a mixed solvatochromic behavior, indicating specific interactions between the self‐assembled scaffold and solvents with varying polarities, as evidenced by transmission electron microscopy (TEM). Moreover, the same light‐induced technique can also be applied for bulk photopolymerization showcasing the versatility and wide‐ranging scope of the originated method. In brief, this study introduces a novel approach for light‐induced polymerization reactions th...
A novel oxygen-tolerant visible light photoinitiating system based on in-situ generation of Fento... more A novel oxygen-tolerant visible light photoinitiating system based on in-situ generation of Fenton reagents using mesoporous graphitic carbon nitride (mpg-C 3 N 4) in conjunction with FeCl 3 •6H 2 O, water and oxygen for free radical polymerization is described. A mpg-C 3 N 4catalysed photoinduced electron transfer reactions of water/oxygen and Fe 3+ were demonstrated to enable generation of hydroxyl radicals that are capable of initiating the polymerization of mono and bifunctional monomers. The efficiency of the photoinitiation is controlled by specific surface area of the carbon nitride. Apparently, non-porous carbon nitrides did not yield polymers under the given conditions. Due to its heterogeneous nature, after the polymerization, although at lower rate, separated mpg-C 3 N 4 could be used for further polymerizations.
The emergence, historical and recent developments of phenolic resins are reviewed. The history of... more The emergence, historical and recent developments of phenolic resins are reviewed. The history of the invention of the first man made plastics and a short bibliography of the inventor Leo H. Baekeland is provided. Moreover, the basic chemistry of phenol‐formaldehyde resins, as synthesis of resol and novolak, their structures, variations, and curing are discussed. Modification of these resins and molecular designs for specific applications in retro perspective are highlighted. This review also provides a comprehensive account on the development of benzoxazine resins as an alternative to classical phenolics. In addition to the benzoxazine synthesis and their curing mechanism, special monomers and polybenzoxazine precursors as curable thermoplastics are reviewed. Besides classical chemicals, the potential of renewables for phenolic resin production is also highlighted. Finally, the relative advantages and disadvantages of these systems are discussed and their future potentials are pres...
The uniform microporous organic polymer (MOP) was obtained in one-pot and one-step polymerization... more The uniform microporous organic polymer (MOP) was obtained in one-pot and one-step polymerization process through Schiff base chemistry under thermal conditions. The obtained anthraquinone-melamine based MOP (AM-MOP) displays high surface area (215 m 2 /g). AM-MOP was manually filled into a column with high pressure and used as packing material in the high-performance liquid chromatographic applications. The analysis of compounds such as polycyclic aromatic hydrocarbons, pesticides, flavonoids, and phenolic acids was performed to display a possible application by using AM-MOP packed column. Compared to the commercial columns, AM-MOP exhibits better selectivity factor and column efficiency arising from its strong π-π interaction activity. Furthermore, it has similar solvent uptake in both polar and nonpolar media, which explains good compatibility of the material with all mobile phases, from acetonitrile to methanol and water.
Microporous materials, i.e. materials having pore sizes smaller than 2 nm, which are based on pur... more Microporous materials, i.e. materials having pore sizes smaller than 2 nm, which are based on purely organic precursors have attracted considerable scientific interest due to applications in the fields of gas storage, gas separation, and heterogeneous catalysis.
ABSTRACT A novel synthetic procedure is reported for the preparation of block copolymers by means... more ABSTRACT A novel synthetic procedure is reported for the preparation of block copolymers by means of successive 1,3-benzoxazine-thiol and Husigen type azide-alkyne coupling methodologies in one-pot and sequential synthesis. The applied 1,3-benzoxazine-thiol process based on catalytic opening of the lateral benzoxazine rings by thiols is proposed as a new thiol-X chemistry. Azide functional poly(methyl acrylate) (PMA-N-3), poly(ethylene glycol) (PEG-N-3) and thiol functional polystyrene (PS-SH) were prepared. The obtained PMA-N-3 or PEG-N-3, PS-SH and propargyl benzoxazine as a click-linker were reacted in sequential or one-pot two step manner to yield desired PS-b-PMA and PS-b-PEG block copolymer. The described thiol-benzoxazine chemistry offers a facile and efficient route to exploring the many possibilities in macromolecular synthesis.
Novel side-chain benzoxazine functional polybutadiene (PB-benzoxazine) was synthesized by using c... more Novel side-chain benzoxazine functional polybutadiene (PB-benzoxazine) was synthesized by using click chemistry strategy. First, some of double bonds were brominated with Br 2 in CCl 4 and subsequently converted to azido groups by using NaN 3 in DMF. Propargyl benzoxazine was prepared independently by a ring-closure reaction between p-propargyloxy aniline, paraformaldehyde and phenol. Finally, azidofunctionalized polybutadiene was coupled to propargyl benzoxazine with high efficiency by click chemistry. The spectral and thermal analysis confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that PB-benzoxazine undergoes thermally activated curing in the absence of any catalyst forming polybutadiene thermoset with high char yield.
The use mesoporous graphitic carbon nitride (mpg-C 3 N 4) in conjunction with tertiary amines as ... more The use mesoporous graphitic carbon nitride (mpg-C 3 N 4) in conjunction with tertiary amines as initiators in visible-lightinduced free radical polymerization is described. The initiation mechanism involves photoinduced free radical generation by scavenging holes with amines and subsequent hydrogen abstraction. The efficiency of the photoinitiation is controlled by the nature of the amines and specific surface area of the carbon nitride powder. Apparently, amines with higher basicity and available hydrogens provide more favorable conditions for the photoinitiation process. Due to its heterogeneous nature, the photoinitiator preserves its photoinitiation activity after the polymerization and can easily be separated and used for further polymerizations.
A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemi... more A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemistry. The chemical structure of OThiophenePS was characterized by nuclear magnetic resonance (1 H NMR) and Fourier transform infrared (FT-IR) spectroscopies. Electrochemical polymerization of pyrrole with OThiophenePS was performed resulting in polypyrrole-attached, polyhedral oligomeric silsesquioxane (OPS-PPy). The spectroelectrochemical studies show that the electrochromic properties of (OPS-PPy) are superior to those of polypyrrole (PPy). This great improvement can be attributed to the more accessible doping sites and the facile ion movement during the redox switching brought by the loose packing of the PPy chains.
Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of... more Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of interesting features and the capability to overcome several shortcomings of conventional novolac and resole type phenolic resins. These materials exhibit (i) near-zero volumetric change upon curing, (ii) low water absorption, (iii) for some polybenzoxazines T g much higher than cure temperature, (iv) high char yield, (v) no strong acid catalysts required for curing, and (vi) release of no toxic by-product during curing. The molecular structure of polybenzoxazines offers enormous design flexibility, which allows tailoring the properties of the cured materials for a wide range of applications. In this review article, different synthetic strategies for the preparation of benzoxazine monomers and blends, their polymerization reaction mechanisms, and the structure-property relationships of the cured materials have been discussed.
Synthesis of high-performance polymers and their high-tech applications have attracted significan... more Synthesis of high-performance polymers and their high-tech applications have attracted significant attention in recent years. Conventional polymers do not offer the properties associated with thermoset polymers, and hence their applications as highperformance polymers are limited. Thermoset polymers are normally synthesized using step-growth methods where chain growth and cross-linking processes arise from the same type of chemical reaction. 1 However, thermoset polymers are not easily processable, their manufacturing is not cost-effective, and thus they remain prohibitively expensive for these applications. Cross-linking of linear polymers is one approach to improve the properties and consequently to access the demanding regimes of high-tech applications. Cross-linking of conventional polymers is readily achieved by the incorporation of a multifunctional monomer during the polymerization process. 2-6 High
In this paper, synthetic strategies for the preparation of structurally different polymers, namel... more In this paper, synthetic strategies for the preparation of structurally different polymers, namely polystyrene (PSt), poly(ε‐caprolactone) (PCL), poly(propyleneoxide) (PPO), poly(methyl methacrylate) (PMMA), and poly(styrene‐alt‐ maleimide) (PSt‐alt‐MI) with thermally curable benzoxazine groups have been outlined. Specifically, these groups were incorporated into PSt and PCL by using two controlled polymerization methods, namely Atom Transfer Radical Polymerization (ATRP) and Ring Opening Polymerization (ROP), respectively. Modification of linear and branched poly(propylene amine)s via Mannich reaction yields the corresponding benzoxazine functional PPOs. The photoinitiated polymerization of olefinic monomers such as methyl methacrylate by using benzoxazines as hydrogen donor in conjunction with aromatic carbonyl compounds is another suitable method for the desired functionalization. Moreover, benzoxazine substituted maleimide was copolymerized with styrene to yield perfectly altern...
Summary: Free radical polymerization of methyl methacrylate (MMA) is initiated upon irradiation a... more Summary: Free radical polymerization of methyl methacrylate (MMA) is initiated upon irradiation at λ > 350 nm in CH2Cl2 that contains benzoxazine (P‐a) and one of the following photosensitizers: benzophenone (BP), thioxanthone (TX), 2‐chlorothioxanthone (CTX), 2‐isopropyl thioxanthone (ITX), and camphorquinone (CQ). The postulated mechanism is based on the intermolecular reaction of the excited photosensitizer with the tertiary amino moiety of the ground state P‐a and a subsequent hydrogen abstraction reaction. The resulting aminoalkyl radicals initiate the polymerization. The incorporation of P‐a groups into polymers is demonstrated by spectroscopic methods. The possibility of deep curing using the described photoinitiating system followed by the thermal ring opening of the incorporated P‐a groups is also demonstrated.Schematic of the photoinitiated free radical polymerization using benzoxazines as hydrogen donors.magnified imageSchematic of the photoinitiated free radical polym...
Visible light‐induced reverse and simultaneous reverse and normal initiation (SR&NI) atom transfe... more Visible light‐induced reverse and simultaneous reverse and normal initiation (SR&NI) atom transfer radical polymerizations of vinyl monomers are examined using various dyes and type I photoinitiators. The effect of photoinitiator types on the control of molecular weight and distribution is described. In both dye and type I photoinitiator sensitized SR&NI ATRP systems, the molecular weights increase linearly with conversion. However, the experimental molecular weights are considerably higher than the theoretical values and the polymers show broad‐molecular‐weight distributions ranging from 1.28 to 1.60 in the dye‐sensitized SR&NI ATRP. However, the polymers obtained by SR&NI ATRP using type I photoinitiator system had molecular weight values close to the theoretical ones and very narrow‐molecular‐weight distributions ranging from 1.11–1.18.
Journal of Polymer Science Part A: Polymer Chemistry, 2008
Novel side-chain benzoxazine functional polyvinylchloride (PVC-Benzoxazine) was synthesized by us... more Novel side-chain benzoxazine functional polyvinylchloride (PVC-Benzoxazine) was synthesized by using ''Click Chemistry'' strategy. First, approximately 10% of chloro groups of PVC were converted to azido groups by using NaN 3 in N,N-dimethylformamide. Propargyl benzoxazine was prepared independently by a ring closure reaction between p-propargyloxy aniline, paraformaldehyde, and phenol. Finally, azidofunctionalized PVC was coupled to propargyl benzoxazine with high efficiency by click chemistry. The spectral and thermal analysis confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that PVC containing benzoxazine undergoes thermally activated curing in the absence of any catalyst forming PVC thermoset with high thermal stability. V
A straightforward approach was employed to synthesize methylene‐bridged poly(hetero aromatic)s ba... more A straightforward approach was employed to synthesize methylene‐bridged poly(hetero aromatic)s based on furan, pyrrole, thiophene, and thiophene derivatives. The process involved an electrophilic aromatic substitution reaction facilitated by a visible light‐initiated system consisting of manganese decacarbonyl and an iodonium salt. The approach mainly relies on the formation of halomethylium cation, the attack of this cation to heteroaromatic, regeneration of methylium cation on the heteroaromatic, and reactivity differences between halomethylium and heteroaromatic methylium cations for successful polymerizations. This innovative synthetic strategy led to the formation of polymers with relatively high molecular weights as the stoichiometric imbalance between the comonomers increased. Accordingly, these newly obtained polymers exhibited remarkable fluorescence properties, even at excitation wavelengths as low as 330 nm. Moreover, by harnessing the halogens at chain ends of homopolyme...
A novel method based on light‐induced fabrication of a poly (3,4‐ethylenedioxythiophene)‐polycapr... more A novel method based on light‐induced fabrication of a poly (3,4‐ethylenedioxythiophene)‐polycaprolactone (PEDOT‐PCL) scaffold using phenacyl bromide (PAB) as a single‐component photoinitiator is presented. HBr released from the step‐growth polymerization of EDOT is utilized as an in situ catalyst for the chain‐growth polymerization of ε‐caprolactone. Detailed investigations disclose the formation of a self‐assembled nanoporous electroconductive scaffold (1.2 mS cm−1). Fluorescence emission spectra of the fabricated scaffold exhibit a mixed solvatochromic behavior, indicating specific interactions between the self‐assembled scaffold and solvents with varying polarities, as evidenced by transmission electron microscopy (TEM). Moreover, the same light‐induced technique can also be applied for bulk photopolymerization showcasing the versatility and wide‐ranging scope of the originated method. In brief, this study introduces a novel approach for light‐induced polymerization reactions th...
A novel oxygen-tolerant visible light photoinitiating system based on in-situ generation of Fento... more A novel oxygen-tolerant visible light photoinitiating system based on in-situ generation of Fenton reagents using mesoporous graphitic carbon nitride (mpg-C 3 N 4) in conjunction with FeCl 3 •6H 2 O, water and oxygen for free radical polymerization is described. A mpg-C 3 N 4catalysed photoinduced electron transfer reactions of water/oxygen and Fe 3+ were demonstrated to enable generation of hydroxyl radicals that are capable of initiating the polymerization of mono and bifunctional monomers. The efficiency of the photoinitiation is controlled by specific surface area of the carbon nitride. Apparently, non-porous carbon nitrides did not yield polymers under the given conditions. Due to its heterogeneous nature, after the polymerization, although at lower rate, separated mpg-C 3 N 4 could be used for further polymerizations.
The emergence, historical and recent developments of phenolic resins are reviewed. The history of... more The emergence, historical and recent developments of phenolic resins are reviewed. The history of the invention of the first man made plastics and a short bibliography of the inventor Leo H. Baekeland is provided. Moreover, the basic chemistry of phenol‐formaldehyde resins, as synthesis of resol and novolak, their structures, variations, and curing are discussed. Modification of these resins and molecular designs for specific applications in retro perspective are highlighted. This review also provides a comprehensive account on the development of benzoxazine resins as an alternative to classical phenolics. In addition to the benzoxazine synthesis and their curing mechanism, special monomers and polybenzoxazine precursors as curable thermoplastics are reviewed. Besides classical chemicals, the potential of renewables for phenolic resin production is also highlighted. Finally, the relative advantages and disadvantages of these systems are discussed and their future potentials are pres...
The uniform microporous organic polymer (MOP) was obtained in one-pot and one-step polymerization... more The uniform microporous organic polymer (MOP) was obtained in one-pot and one-step polymerization process through Schiff base chemistry under thermal conditions. The obtained anthraquinone-melamine based MOP (AM-MOP) displays high surface area (215 m 2 /g). AM-MOP was manually filled into a column with high pressure and used as packing material in the high-performance liquid chromatographic applications. The analysis of compounds such as polycyclic aromatic hydrocarbons, pesticides, flavonoids, and phenolic acids was performed to display a possible application by using AM-MOP packed column. Compared to the commercial columns, AM-MOP exhibits better selectivity factor and column efficiency arising from its strong π-π interaction activity. Furthermore, it has similar solvent uptake in both polar and nonpolar media, which explains good compatibility of the material with all mobile phases, from acetonitrile to methanol and water.
Microporous materials, i.e. materials having pore sizes smaller than 2 nm, which are based on pur... more Microporous materials, i.e. materials having pore sizes smaller than 2 nm, which are based on purely organic precursors have attracted considerable scientific interest due to applications in the fields of gas storage, gas separation, and heterogeneous catalysis.
ABSTRACT A novel synthetic procedure is reported for the preparation of block copolymers by means... more ABSTRACT A novel synthetic procedure is reported for the preparation of block copolymers by means of successive 1,3-benzoxazine-thiol and Husigen type azide-alkyne coupling methodologies in one-pot and sequential synthesis. The applied 1,3-benzoxazine-thiol process based on catalytic opening of the lateral benzoxazine rings by thiols is proposed as a new thiol-X chemistry. Azide functional poly(methyl acrylate) (PMA-N-3), poly(ethylene glycol) (PEG-N-3) and thiol functional polystyrene (PS-SH) were prepared. The obtained PMA-N-3 or PEG-N-3, PS-SH and propargyl benzoxazine as a click-linker were reacted in sequential or one-pot two step manner to yield desired PS-b-PMA and PS-b-PEG block copolymer. The described thiol-benzoxazine chemistry offers a facile and efficient route to exploring the many possibilities in macromolecular synthesis.
Novel side-chain benzoxazine functional polybutadiene (PB-benzoxazine) was synthesized by using c... more Novel side-chain benzoxazine functional polybutadiene (PB-benzoxazine) was synthesized by using click chemistry strategy. First, some of double bonds were brominated with Br 2 in CCl 4 and subsequently converted to azido groups by using NaN 3 in DMF. Propargyl benzoxazine was prepared independently by a ring-closure reaction between p-propargyloxy aniline, paraformaldehyde and phenol. Finally, azidofunctionalized polybutadiene was coupled to propargyl benzoxazine with high efficiency by click chemistry. The spectral and thermal analysis confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that PB-benzoxazine undergoes thermally activated curing in the absence of any catalyst forming polybutadiene thermoset with high char yield.
The use mesoporous graphitic carbon nitride (mpg-C 3 N 4) in conjunction with tertiary amines as ... more The use mesoporous graphitic carbon nitride (mpg-C 3 N 4) in conjunction with tertiary amines as initiators in visible-lightinduced free radical polymerization is described. The initiation mechanism involves photoinduced free radical generation by scavenging holes with amines and subsequent hydrogen abstraction. The efficiency of the photoinitiation is controlled by the nature of the amines and specific surface area of the carbon nitride powder. Apparently, amines with higher basicity and available hydrogens provide more favorable conditions for the photoinitiation process. Due to its heterogeneous nature, the photoinitiator preserves its photoinitiation activity after the polymerization and can easily be separated and used for further polymerizations.
A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemi... more A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemistry. The chemical structure of OThiophenePS was characterized by nuclear magnetic resonance (1 H NMR) and Fourier transform infrared (FT-IR) spectroscopies. Electrochemical polymerization of pyrrole with OThiophenePS was performed resulting in polypyrrole-attached, polyhedral oligomeric silsesquioxane (OPS-PPy). The spectroelectrochemical studies show that the electrochromic properties of (OPS-PPy) are superior to those of polypyrrole (PPy). This great improvement can be attributed to the more accessible doping sites and the facile ion movement during the redox switching brought by the loose packing of the PPy chains.
Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of... more Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of interesting features and the capability to overcome several shortcomings of conventional novolac and resole type phenolic resins. These materials exhibit (i) near-zero volumetric change upon curing, (ii) low water absorption, (iii) for some polybenzoxazines T g much higher than cure temperature, (iv) high char yield, (v) no strong acid catalysts required for curing, and (vi) release of no toxic by-product during curing. The molecular structure of polybenzoxazines offers enormous design flexibility, which allows tailoring the properties of the cured materials for a wide range of applications. In this review article, different synthetic strategies for the preparation of benzoxazine monomers and blends, their polymerization reaction mechanisms, and the structure-property relationships of the cured materials have been discussed.
Synthesis of high-performance polymers and their high-tech applications have attracted significan... more Synthesis of high-performance polymers and their high-tech applications have attracted significant attention in recent years. Conventional polymers do not offer the properties associated with thermoset polymers, and hence their applications as highperformance polymers are limited. Thermoset polymers are normally synthesized using step-growth methods where chain growth and cross-linking processes arise from the same type of chemical reaction. 1 However, thermoset polymers are not easily processable, their manufacturing is not cost-effective, and thus they remain prohibitively expensive for these applications. Cross-linking of linear polymers is one approach to improve the properties and consequently to access the demanding regimes of high-tech applications. Cross-linking of conventional polymers is readily achieved by the incorporation of a multifunctional monomer during the polymerization process. 2-6 High
In this paper, synthetic strategies for the preparation of structurally different polymers, namel... more In this paper, synthetic strategies for the preparation of structurally different polymers, namely polystyrene (PSt), poly(ε‐caprolactone) (PCL), poly(propyleneoxide) (PPO), poly(methyl methacrylate) (PMMA), and poly(styrene‐alt‐ maleimide) (PSt‐alt‐MI) with thermally curable benzoxazine groups have been outlined. Specifically, these groups were incorporated into PSt and PCL by using two controlled polymerization methods, namely Atom Transfer Radical Polymerization (ATRP) and Ring Opening Polymerization (ROP), respectively. Modification of linear and branched poly(propylene amine)s via Mannich reaction yields the corresponding benzoxazine functional PPOs. The photoinitiated polymerization of olefinic monomers such as methyl methacrylate by using benzoxazines as hydrogen donor in conjunction with aromatic carbonyl compounds is another suitable method for the desired functionalization. Moreover, benzoxazine substituted maleimide was copolymerized with styrene to yield perfectly altern...
Summary: Free radical polymerization of methyl methacrylate (MMA) is initiated upon irradiation a... more Summary: Free radical polymerization of methyl methacrylate (MMA) is initiated upon irradiation at λ > 350 nm in CH2Cl2 that contains benzoxazine (P‐a) and one of the following photosensitizers: benzophenone (BP), thioxanthone (TX), 2‐chlorothioxanthone (CTX), 2‐isopropyl thioxanthone (ITX), and camphorquinone (CQ). The postulated mechanism is based on the intermolecular reaction of the excited photosensitizer with the tertiary amino moiety of the ground state P‐a and a subsequent hydrogen abstraction reaction. The resulting aminoalkyl radicals initiate the polymerization. The incorporation of P‐a groups into polymers is demonstrated by spectroscopic methods. The possibility of deep curing using the described photoinitiating system followed by the thermal ring opening of the incorporated P‐a groups is also demonstrated.Schematic of the photoinitiated free radical polymerization using benzoxazines as hydrogen donors.magnified imageSchematic of the photoinitiated free radical polym...
Visible light‐induced reverse and simultaneous reverse and normal initiation (SR&NI) atom transfe... more Visible light‐induced reverse and simultaneous reverse and normal initiation (SR&NI) atom transfer radical polymerizations of vinyl monomers are examined using various dyes and type I photoinitiators. The effect of photoinitiator types on the control of molecular weight and distribution is described. In both dye and type I photoinitiator sensitized SR&NI ATRP systems, the molecular weights increase linearly with conversion. However, the experimental molecular weights are considerably higher than the theoretical values and the polymers show broad‐molecular‐weight distributions ranging from 1.28 to 1.60 in the dye‐sensitized SR&NI ATRP. However, the polymers obtained by SR&NI ATRP using type I photoinitiator system had molecular weight values close to the theoretical ones and very narrow‐molecular‐weight distributions ranging from 1.11–1.18.
Journal of Polymer Science Part A: Polymer Chemistry, 2008
Novel side-chain benzoxazine functional polyvinylchloride (PVC-Benzoxazine) was synthesized by us... more Novel side-chain benzoxazine functional polyvinylchloride (PVC-Benzoxazine) was synthesized by using ''Click Chemistry'' strategy. First, approximately 10% of chloro groups of PVC were converted to azido groups by using NaN 3 in N,N-dimethylformamide. Propargyl benzoxazine was prepared independently by a ring closure reaction between p-propargyloxy aniline, paraformaldehyde, and phenol. Finally, azidofunctionalized PVC was coupled to propargyl benzoxazine with high efficiency by click chemistry. The spectral and thermal analysis confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that PVC containing benzoxazine undergoes thermally activated curing in the absence of any catalyst forming PVC thermoset with high thermal stability. V
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