Modeling RAFT polymerization kinetics via Monte Carlo methods: cumyl dithiobenzoate mediated methyl acrylate polymerization

Cumyl dithiobenzoate (CDB) mediated methyl acrylate (MA) bulk polymerizations at 80 °C, using CDB concentrations between 1.5×10⁻² and 5.0×10⁻² mol L⁻¹, were modeled via a novel Monte Carlo simulation procedure with respect to experimental time-dependent conversions, X, number average molecular weights, M_n, and weight average molecular weights, M_w. The simulations were based upon individual treatment of 5×10⁸ discrete molecules in accordance to their actual reaction pathways. The kinetic scheme employed includes termination reactions of intermediate RAFT radicals with propagating radicals and reaction steps of the RAFT pre-equilibrium, which are different from those of the RAFT main equilibrium. The equilibrium constant of the main equilibrium of the CDB/MA system at 80 °C was found to be K=1.2×10⁴ L mol⁻¹, indicating a relatively stable intermediate radical. The concentration of the intermediate RAFT radical, although not employed as experimental input data for the modeling, was calculated by using the obtained set of kinetic parameters as being in excellent agreement with experimental electron spin resonance spectroscopic data.     

Synthesis of novel random and block copolymers of tert-butyldimethylsilyl methacrylate and methyl methacrylate by RAFT polymerization

Hydrophobic-hydrolysable copolymers consisting of methyl methacrylate (MMA) and tert-butyldimethylsilyl methacrylate (TBDMSMA) have been synthesized for the first time by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization technique using cumyl dithiobenzoate (CDB) and cyanoisopropyl dithiobenzoate (CPDB) as chain transfer agents (CTAs). The monomer reactivity ratios for TBDMSMA (r₁ = 1.40 ± 0.03) and MMA (r₂ = 1.08 ± 0.03) have been determined using a non-linear least-squares fitting method. Well-defined random copolymers PMMA-co-PTBDMSMA have been prepared. Then, the versatility of the RAFT process to synthesize silylated block copolymers with controlled molecular weights and low polydispersities has been demonstrated using two strategies: the synthesis of PMMA-SC(S)Ph or PTBDMSMA-SC(S)Ph as macro-chain transfer agent (macro-CTA) for use in a two step method or an one-pot method which consists in the successive addition of the two monomers. Diblock copolymers with narrow molecular weight distributions (PDI < 1.2) were obtained from the one-pot method with number-average molecular weight values within the range 10,000-22,000 g mol⁻¹.     

RAFT miniemulsion polymerization of methyl methacrylate

It has been well documented that RAFT miniemulsion polymerization has broader molecular weight distribution, compared with its bulk polymerization counterpart. Interestingly, it was found that the PDI value of RAFT miniemulsion polymerization of methyl methacrylate (MMA) mediated by 2-cyranoprop-2-yl dithiobenzoate (CPDB) was still as low as its corresponding bulk polymerization did. PDI could be as low as 1.13 even with typical sodium dodecyl sulfate (SDS, 1 wt%, surfactant) and n-hexadecane (HD, 2 wt%, costablizer) concentrations. When the polymerization was carried out at 60 °C, a dramatic increase in PDI (>1.4) was observed after 80% monomer conversion since RAFT addition reaction became diffusion-controlled. Increasing the polymerization temperature to 80 °C could reduce the PDI to 1.2 even at 100% monomer conversion. The compartmentalization effect of radicals was surprisingly absence before 30% monomer conversion but became pronounced afterwards in the miniemulsion polymerization. Thus, it still took less time to finish the miniemulsion polymerization with the increase of the surfactant levels.     

双硫酯作为链转移剂的苯乙烯本体聚合研究

研究了二硫代苯甲酸苄基酯（BDB）、二硫代苯甲酸苯乙基酯（PEDB）及二硫代苯甲酸异丙苯基酯（CDB）三种RAFT试剂作为链转移剂的苯乙烯本体聚合。动力学研究表明,当BDB及PEDB浓度和偶氮二异丁腈（AIBN）浓度同时增大时,AIBN浓度提高所导致的聚合反应速率提高起主导作用：当CDB和AIBN浓度同时提高时,CDB浓度提高所导致的聚合速率降低作用影响更显著。对CDB体系,随转化率提高分子量分布变宽。对BDB体系,当其浓度较高时,随转化率提高分子量分布变窄;当其浓度较低时,不利于实现可控,活性聚合,反应后期分子量分布变宽。动力学和GPC分析均表明以BDB为链转移剂时苯乙烯本体聚合的可控性最好。在同时考虑链转移剂和引发剂作用的基础上,提出了修正的聚合物分子量预测模型,该模型可有效预测以双硫酯为链转移剂的苯乙烯RAFT聚合体系的分子量。     

Synthesis and properties of gradient copolymers of butyl methacrylate and fluorinated acrylate via RAFT miniemulsion copolymerizations

A series of gradient fluorinated copolymers with a broad variation of the monomer units in the polymer chain were synthesized via semibatch CPDB‐mediated RAFT miniemulsion polymerization technique. In the presence of RAFT agent 2‐cyanoprop‐2‐yl dithiobenzoate (CPDB), the copolymerization of BMA and FMA in miniemulsion exhibited typical features of a controlled molecular weights and narrow polydispersities. The macromolecular structure and thermal behavior of the synthesized fluorinated copolymers were investigated in detail. The DSC analyses show that the gradient copolymers showed a unique thermal behavior with broad range of transition temperature. It was also confirmed that the fluorinated gradient copolymer exhibited obvious surface segregation structure and ultra‐low surface energy between 16.8 and 20.3 mN/m. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42936.     

Reversible addition-fragmentation chain transfer polymerization of 7-(4-(acryloyloxy)butoxy)coumarin

The light sensitive vinyl monomer with coumarin unit, 7-(4-(acryloyloxy)butoxy)coumarin (7AC), was synthesized. The reversible addition-fragmentation chain transfer (RAFT) polymerization of 7AC, initiated by 2,2′-azobisisobutyronitrile (AIBN), was carried out using 2-cyanoprop-2-yl dithiobenzoate (CPDB) as a RAFT agent in N,N-dimethylformamide (DMF) solution. The kinetics exhibited first-order relationship with respect to the monomer concentration. The molecular weight of the polymer increased linearly with the monomer conversion. The chain extension of poly(7-(4-(acryloyloxy)butoxy)coumarin) (P7AC) using styrene (St) as the second monomer demonstrated that the obtained polymers were almost “living”. The fluorescence intensity of P7AC increased with the molecular weight of P7AC and was stronger than that of the monomer. The obtained polymer had strong ultraviolet (UV) absorption at 322 nm. The molecular weights of the polymer had no effect on its ultraviolet absorption intensity. The coumarin structure existing in P7AC underwent [2 + 2] cycloaddition reaction (photodimerization) under UV irradiation in tetrahydrofuran (THF) solution, which can be further used to prepare small particles from the single polymer.     

First RAFT polymerization of captodative 2-acetamidoacrylic acid (AAA) monomer: An experimental and theoretical study

A capto-dative monomer, 2-acetamidoacrylic acid (AAA), was homopolymerized through RAFT polymerization method using 2-(2-cyanopropanyl dithiobenzoate) (CPDB) as a chain transfer agent and AIBN free radical initiator in DMF at 70 °C. DFT calculations were performed in the selection of the CTA for this unique monomer as well as to elucidate the influence of cd-stabilized growing radical on the kinetic parameters in comparison to methacrylic acid (MAA) and N-(prop-1-en-2-yl)acetamide (NPAA), which represent the captive and dative groups of AAA, respectively. K_eq for these three monomers is in the order of AAA < MAA < NPAA. While k_β > k_−add for NPAA and MAA, for AAA k_−add is about four orders of magnitude larger than k_β. This is the major disadvantage in the RAFT process of AAA using CPDB. Yet, poly(AAA) could be achieved with PDI as low as 1.49. Molecular weight of the polymer can be tuned by the monomer/AIBN ratio. First block copolymers of AAA with MAA and MMA using poly(AAA) as a macro-CTA were also synthesized, indicating the presence of active chain ends.     

RAFT-mediated polymerization and grafting of sodium 4-styrenesulfonate from cellulose initiated via γ-radiation

Ambient temperature (20 °C) reversible addition fragmentation chain transfer (RAFT) polymerization of sodium 4-styrenesulfonate (SS) conducted directly in aqueous media under γ-irradiation at different dose rates (0.09, 0.03 and 0.02 kGy h⁻¹) proceeds in a controlled fashion (typically, M_w/M_n < 1.25) to near quantitative conversions via 4-cyanopentanoic acid dithiobenzoate (CPADB) mediation. By applying CPADB modified cellulose as a macro chain transfer agent, a graft copolymer with SS was prepared in aqueous media under γ-irradiation. RAFT mediated graft polymerizations provided copolymers with higher graft frequencies compared to those obtained by conventional methods. Thermally initiated grafting of SS from a CPADB-functionalized cellulose surface at 70 °C was also studied which resulted in a reduced graft frequency in comparison to γ-initiated ones.     

Honeycomb structured porous films from amphiphilic block copolymers prepared via RAFT polymerization

The synthesis of polystyrene-block-poly(N,N-dimethylacrylamide) (PS-b-PDMA) via RAFT polymerization was investigated in detail. Two different RAFT agents - benzyl dithiobenzoate and 3-(benzylsulfanylthiocarbonylsufanyl) propionic acid, were employed to prepare polystyrene macroRAFT agents with molecular weights varying between 3000 g mol⁻¹ and 62,000 g mol⁻¹ and polydispersities between 1.1 and 1.4. Chain extensions with N,N-dimethylacrylamide (DMA) were carried out using a constant monomer to RAFT agent concentration ([DMA]/[RAFT] = 500), to compare the rate of polymerization in dependency of the polystyrene chain length. A decreasing rate of polymerization with increasing block length was observed. Depending on the sizes of the first block and type of RAFT agents used, chain extension polymerization with DMA was found to be incomplete, leading to significant low molecular weight tailing in the GPC analyses. Block copolymers prepared using 3-(benzylsulfanylthiocarbonylsufanyl) propionic acid, followed the expected molecular weight evolutions with polydispersity indices of 1.2-1.4. In contrast, block copolymers using benzyl dithiobenzoate clearly showed bimodal molecular weight distributions, especially when the longest PS macroRAFT agent with a molecular weight of 38,000 g mol⁻¹ was employed. These amphiphilic block copolymers were used to fabricate honeycomb structured porous films using the breath figure technique. The regularity of the film was considerably influenced by the humidity of the environment, which could be controlled by the rate of the airflow or the humidity in the casting chamber. The interaction between the hydrophilic block copolymer and the humidity was found responsible for the delicate equilibrium during the casting process, which prevented high pores regularity at very low (below 50%) and at elevated (above 80%) humidity. The interactions of the hydrophilic block with the humidity were observed to superimpose an additional nano-scaled order onto the hexagonal micron-sized porous array. Pores, which are created by encapsulation of water droplets, were found to be more hydrophilic than the surface. Confocal microscopy studies were employed to locate hydrophilic blocks within the film using a fluorescence labeled PDMA polymer.     

Molecular composite materials formed from block copolymers containing a side-chain liquid crystalline segment and an amorphous styrene/maleic anhydride segment

Side-chain liquid crystalline block polymers containing a poly[6-[4-(4′-methoxyphenyl)phenoxy]hexyl methacrylate] (PMMA-LC) segment and a styrene-co-maleic anhydride segment (alternating structure) were prepared via reversible addition fragmentation chain transfer (RAFT) polymerization. PMMA-LC was initially prepared via RAFT polymerization mediated by 2-(2-cyanopropyl)dithiobenzoate (CPDB). The resulting polymer was subsequently isolated and used to re-initiate styrene/maleic anhydride alternating copolymerization. The block copolymerization proceeded to intermediate conversions with narrow polydispersities, however at higher conversions some molecular weight broadening was observed and this was attributed to radical-radical termination reactions. The resulting polymers were analyzed via size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Microporous honeycomb structured films were cast from solutions of the block copolymers to form porous molecular composites.     

Synthesis of azobenzene-functionalized star polymers via RAFT and their photoresponsive properties

Azobenzene-functionalized star polymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. First, azobenzene-functionalized linear macro chain transfer agents (Macro-CTA) were synthesized by RAFT polymerization of 6-[4-(4′-Methoxyphenylazo)phenoxy]hexylmethacrylate (MAz6Mc) using 2-(2′-cyanopropyl)dithiobenzoate (CPDB) as RAFT agent in presence of AIBN as initiator in anisole. Subsequently, star azopolymers were synthesized by polymerization of a difunctional azomonomer, BMA2Az, with resultant Macro-CTA in presence of AIBN as initiator in anisole. Star azopolymers were characterized by GPC and spectroscopic methods. Thermal properties of star azopolymers were determined by DSC and TMA. Molecular weight versus conversion and molecular weight versus polymerization time attest to living polymerization characteristics. Photoisomerization behaviors of star azopolymers were studied by irradiation of both UV and visible light. Surface relief gratings were inscribed on star azopolymer films upon exposure to an interference pattern of (RCP + RCP) Ar⁺ laser. A diffraction efficiency of 20% was obtained by exposure of Star-8 K(2.6 K) polymer film to an (RCP + RCP) Ar⁺ laser for about 30 min. Surface relief grating structures were investigated by AFM and polarized optical microscopy.     

RAFT Polymerization of Methyl Acrylate in Carbon Dioxide

Summary: Reversible addition fragmentation chain transfer (RAFT) polymerizations of methyl acrylate (MA) in solution containing either 22 vol.‐% CO₂ or toluene were performed at 80 °C and 300 bar using cumyl dithiobenzoate (CDB) at concentrations between 1.8 × 10^?3 to 2.5 × 10^?2 mol · L^?1 as the RAFT agent. Product molecular weight distributions and average molecular weights indicated the successful control of MA polymerization in CO₂, even at low CDB concentrations. RAFT polymerization rates were strongly retarded by CDB and were lower in CO₂ than in toluene solution. The enhanced fluidity associated with the addition of CO₂ to the polymerizing system provided access to mechanistic details of RAFT polymerization. The data of the present study into MA, together with our recent results on RAFT polymerization of styrene in solution of CO₂ and of toluene, suggest that self‐termination of intermediate RAFT radicals is responsible for retardation in case of high concentrations of this intermediate and in case of enhanced fluidity, which may be achieved by polymerization in solution of CO₂.

     

Co γ-irradiation-initiated RAFT polymerization of VAc at room temperature

In this work, the reversible addition-fragmentation chain transfer (RAFT) polymerization of vinyl acetate (VAc) was successfully performed at room temperature using ⁶⁰Co γ-irradiation as the initiation source. Under the dose rate of 10 Gy/min irradiation, the polymerization proceeded smoothly and converted approximately 90% of the monomer within 7 h. The molecular weight distribution (M_w/M_n) remained narrow (M_w/M_n < 1.35) up to 90% conversion. Compared to AIBN-initiated RAFT polymerization at 60 °C, ⁶⁰Co γ-irradiation-initiated RAFT polymerization is a technique that can better control the molecular weight, especially at high conversion. The ¹H NMR spectra and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry confirmed that most of the chain ends of poly(VAc) (PVAc) from γ-irradiated RAFT polymerization were living and can be reactivated for chain-extension reactions. The microstructures of PVAc from ⁶⁰Co γ-irradiated RAFT polymerization (almost head-to-tail addition) and AIBN-initiated RAFT polymerization (5% tail-to-tail addition) were different, as revealed by the ¹³C NMR spectra. For the first time, ⁶⁰Co γ-irradiation was used as an initiation source for RAFT polymerization of VAc at room temperature.     

Conventional and RAFT miniemulsion copolymerizations of butyl methacrylate with fluoromethacrylate and monomer reactivity ratios

Reversible addition fragmentation chain transfer (RAFT) mediated and conventional miniemulsion copolymerizations of butyl methacrylate (BMA) with fluoromethacrylate (FMA) were carried out at 70°C with potassium persulphate as initiator. The kinetics of the copolymerizations was investigated comparatively. Copolymer compositions at low conversion levels were determined by ¹H NMR and FTIR spectra techniques. In the presence of RAFT agent 2‐cyanoprop‐2‐yl dithiobenzoate, the copolymerization of BMA with FMA in miniemulsion was obviously retarded. The copolymerization exhibited typical features of controlled molecular weights and narrow polydispersities. The reactivity ratios were evaluated by Kellen‐Tudos (K‐T) method, which yields the apparent reactivity ratios: r_BMA = 0.73 and r_FMA = 0.75 in conventional copolymerizations, and r_BMA = 0.65 and r_FMA = 0.70 in CPDB‐mediated system. The results show that the monomer FMA with a perfluoroalkyl side chain is slightly more reactive than BMA, and the copolymerizations process have a tendency to crosspropagate and to produce a higher FMA content in the copolymers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

A new selenium-based RAFT agent for surface-initiated RAFT polymerization of 4-vinylpyridine

A new selenium-based reversible addition-fragmentation chain transfer (RAFT) agent, 4-cyanopentanoic acid diselenobenzoate (RAFT-Se), was synthesized and utilized in the surface-initiated RAFT polymerization of 4-vinylpyridine (4VP) on silicon substrate. The results indicate that the RAFT-Se can control the surface-initiated RAFT polymerization, as evidenced by the number-average molecular weight that increase linearly with monomer conversion, molecular weights that agreed well with the predicted values, and the relatively low polydispersity indexes. The surface-initiated RAFT polymerization with the RAFT-Se was the same polymerization mechanism as its analog, 4-cyanopentanoic acid dithiobenzoate (RAFT-S). The grafting density of the poly(4-vinylpyridine) brushes prepared in the presence of RAFT-Se (σ_RAFT-Se) and RAFT-S (σ_RAFT-S) was estimated to be about 0.51 and 0.66 chains/nm², respectively. In addition, the end of polymer chains on silicon substrate contains selenium element which may be useful in biosensor applications.     

RAFT polymerization of hydrophobic acrylamide derivatives

Several hydrophobic acrylamide derivatives: the N-tert-butylacrylamide (TBAm), the N-octadecylacrylamide (ODAm) and the N-diphenylmethylacrylamide (DPMAm) have been polymerized by reversible addition-fragmentation chain transfer (RAFT) process in the presence of azobis(isobutyronitrile) (AIBN) and tert-butyl dithiobenzoate (tBDB) as initiator and reversible chain transfer agent (CTA), respectively. Homopolymerizations were compared as regards to kinetics and molecular weight (MW) control, and the results were discussed according to the monomer structure and to the influence of several experimental parameters, such as the [CTA]/[AIBN] ratio and the [Monomer]/[CTA] ratio. TBAm and ODAm monomers exhibited a well controlled polymerization (polydispersity index (PDI) below 1.3 for number average molecular weight (M_n) until 30,000 g mol⁻¹) over a wide range of conversion (until 70%), whereas DPMAm conversion remained below 20% partly due to steric hindrance. The molecular weights of several poly(TBAm) samples determined by four independent analytical techniques, size exclusion chromatography/on-line light scattering detector (SEC/LSD), ¹H NMR, ¹³C NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), were in agreement, close to the theoretical ones. Moreover, the MALDI-TOF MS analyses suggested the presence of parasite chains resulting from irreversible termination onto RAFT intermediate radicals.     

Using dilatometry in the reversible addition fragmentation transfer polymerization of N-(S)-(−)-α-methylbenzyl methacryloylamine

Optically active polymers were prepared using reversible addition-fragmentation chain transfer polymerization (RAFT) of N-(S)-α-methylbenzylmethacryloylamine (N-(S)-α-MBMA), a functional optically active monomer. RAFT polymerizations were carried out at 70 °C in ethanol using AIBN as a thermal initiator and benzyl or (1-phenyl)ethyl dithiobenzoate (BDB and PEDB, respectively) as the RAFT agents. The kinetic study was performed by dilatometry. Plots of conversion vs time indicated that the polymerizations followed first order kinetics. ¹H NMR, IR, and UV–vis spectrophotometric studies confirmed the presence of thiocarbonylthio moieties (−SCS-) in the polymer chains. The molecular weight distributions (MWDs) were moderately narrow with polydispersity indices between 1.3 and 1.6, which indicated that the control of the reaction was not completely achievement using BDB or PEDB as RAFT agents. The optical activity [α]_D²⁵ measurements of synthesized polymers by RAFT did not show a noticeably linear increase dependence with respect to molecular weight, as was previously reported for another controlled free radical polymerization (CRP) system.     

RAFT‐mediated graft polymerization of glycidyl methacrylate in emulsion from polyethylene/polypropylene initiated with γ‐radiation

The successful reversible addition‐fragmentation (RAFT)‐mediated graft polymerization of glycidyl methacrylate (GMA) in emulsion phase from polyethylene/polypropylene nonwoven fabric using 4‐cyano‐4‐[(phenylcarbonothioyl)thio]pentanoic acid under γ‐irradiation at ambient condition is reported. While conventional graft polymerization in emulsion phase yielded grafted materials with low of grafting (Dg) values [<7.5% at 10% (wt/wt) GMA], addition of RAFT agent to the graft polymerization system allowed the synthesis of polyethylene/polypropylene‐g‐poly(GMA) with more tunable Dg (8% ≤ Dg ≤ 94%) by controlling the grafting parameters. Relatively good control (PDI ～1.2 for selected grafting conditions) during polymerization was attained at 100:1 monomer‐to‐RAFT agent molar ratio. The number average molecular weight of free poly(glycidyl methacrylate) (PGMA) increased as a function of monomer conversion. NMR analyses of the free PGMA homopolymers indicate the presence of dithiobenzoate group from 4‐cyano‐4‐((phenylcarbonothioyl)thio) pentanoic acid on the polymer chain. The reactive pendant oxirane group of the grafted GMA can be modified for various environmental and industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45270.     

Preparation and characterization of novel side-chain azobenzene polymers containing tetrazole group

A novel methacrylate monomer containing azobenzene chromophore and tetrazole moiety, 4′-(2-methacryloxyethyl)methylamino-4-(5-chlorotetrazol-1-yl)azobenzene (MACA), was synthesized and polymerized to form homopolymer (PMACA) via reversible addition-fragmentation chain transfer (RAFT) polymerization using 2-cyanoprop-2-yl dithiobenzoate (CPDB) as the RAFT agent and azobisisobutyronitrile (AIBN) as an initiator in dimethyl formamide (DMF) solution. Meanwhile, block copolymers (PMMA-b-PMACAs) were successfully obtained by RAFT polymerization of MACA using PMMA as the macro-RAFT agent and AIBN as an initiator. Gel permeation chromatography (GPC) characterization indicated that polymers with well-controlled molecular weights and narrow molecular weight distributions (M_w/M_ns < 1.30) were obtained. The structures of these polymers were characterized by ¹H NMR and FT-IR spectra. Thermal and photoisomerization behaviors of the polymers indicated that these polymers were amorphous state with good heat stability and photoisomerization performance. Relationship between the electrochemical behavior of block copolymer (PMMA-b-PMACA) and the photoisomerization of azobenzene was investigated by cyclic voltammetry (CV) in chloroform solution, which showed that the oxidation peak of copolymer shifted from 1.0 V to 0.6 V during azobenzene isomerization from trans to cis form. Furthermore, surface relief gratings (SRGs) formed on the films of PMMA-b-PMACAs were also investigated with illumination of a linearly polarized Kr⁺ laser beam. The diffraction efficiency of the SRGs was 1.22 (PMMA-b-PMACA1), 2.38 (PMMA-b-PMACA2) and 3.02 (PMMA-b-PMACA3), respectively, which increased with the azobenzene contain for the copolymers.     

RAFT polymerization of styrene mediated by naphthalene-containing RAFT agents and optical properties of the polymers

In this paper, we designed and synthesized five novel reversible addition–fragmentation chain transfer (RAFT) agents bearing naphthyl moieties in the Z or R groups, including 3,4,5-trimethoxy-benzyl dithio-2-naphthalenoate (TOBDN), 4-nitrobenzyl dithio-2-naphthalenoate (NBDN), 1-menaphthyl 4-cyanodithiobenzoate (NCDB), 1-menaphthyl dithiobenzoate (NDB) and 1-menaphthyl dithio-2-naphthalenoate (NDN). The RAFT polymerizations of styrene mediated by these RAFT agents with AIBN as the initiator at 80 °C were conducted and evaluated. Except for NCDB, the RAFT agents showed good control over the polymerization at different RAFT agent concentrations: the M_n,GPC increased linearly with the monomer conversion, and the PDIs of the polymers were relatively low (PDI = 1.20–1.50). The structure of RAFT agents bearing three different R groups with naphthyl as the Z group showed less effects on the polymerization rate, while those bearing different Z groups with 1-menaphthyl as the R group presented significant effects on the polymerization rates. The polymerization rate with phenyl as the Z group was higher than that with 2-naphthyl as the Z group, and it decreased significantly when using 4-cycno phenyl as the Z group. Retardation effects were observed with all the RAFT agents. ¹H NMR spectra and chain extension results confirmed that most of the polymer chains were “living”. Ultraviolet (UV) absorption of naphthyl moieties at the R group showed blue shifts compared with those of naphthyl at the Z group. The UV absorption intensity of PS was uniformly lower than that of the corresponding RAFT agent, while the fluorescence intensity of PS was higher than that of the corresponding RAFT agent.