One‐pot synthesis of hyperbranched polyamines based on novel amino glycidyl ether

We report a one‐pot synthesis of hyperbranched polyglycerols possessing amino functionality by using a novel Boc‐protected aminoethanol glycidyl ether monomer (BAG). A series of hyperbranched Boc‐protected polyamino glycerols (PBAG) were prepared through a one‐pot anionic ring opening multibranching polymerization to yield PBAG with controlled molecular weights (3500–17400 g/mol). Subsequent deprotection of PBAG yielded hyperbranched polyamino glycerols (PAG) with a globular polymeric structure that comprises a randomly branched structure with a large number of functional amine and hydroxyl groups. ¹H, ¹³C, and ¹⁵N‐NMR, GPC, and MALDI‐TOF measurements confirmed the successful polymerization of the hyperbranched PAG polymers. With its superior biocompatibility of PAG, we anticipate the prospective potentials for the applications in biological and biomedical fields. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 4013–4019     

Architecture‐controlled synthesis of redox‐degradable hyperbranched polyglycerol block copolymers and the structural implications of their degradation

We have successfully synthesized a series of redox‐degradable hyperbranched polyglycerols using a disulfide containing monomer, 2‐((2‐(oxiran‐2‐ylmethoxy)ethyl)disulfanyl) ethan‐1‐ol (SSG), to yield PSSG homopolymers and hyperbranched block copolymers, P(G‐b‐SSG) and P(SSG‐b‐G), containing nondegradable glycerol (G) monomers. Using these polymers, we have explored the structures of the hyperbranched block copolymers and their related degradation products. Furthermore, side reaction such as reduction of disulfide bond during the polymerization was investigated by employing the free thiol titration experiments. We elucidated the structures of the degradation products with respect to the architecture of the hyperbranched block copolymer under redox conditions using ¹H NMR and GPC measurements. For example, the degradation products of P(G‐b‐SSG) and P(SSG‐b‐G) are clearly different, demonstrating the clear distinction between linear and hyperbranched block copolymers. We anticipate that this study will extend the structural diversity of PG based polymers and aid the understanding of the structures of degradable hyperbranched PG systems. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1752–1761     

Synthesis,Characterization, and thermoresponsive properties of Helical Polypeptides Derivatized from Poly(γ−4‐(3‐chloropropoxycarbonyl)benzyl‐L‐glutamate)

A series of side‐chain‐functionalized α‐helical polypeptides, i.e., poly(γ‐4‐(3‐chloropropoxycarbonyl)benzyl‐_L‐glutamate) (6) have been prepared from n‐butylamine initiated ring‐opening polymerization (ROP) of γ‐4‐(3‐chloropropoxycarbonyl)benzyl‐_L‐glutamic acid‐based N‐carboxyanhydride. Polypeptides bearing oligo‐ethylene‐glycol (OEG) groups or 1‐butylimidazolium salts were prepared from 6 via copper‐mediated [2+3] alkyne‐azide 1,3‐dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α‐helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side‐chains showed reversible LCST‐type phase transition behaviors in water while polymers bearing 1‐butylimidazolium and I^? counter‐anions exhibited reversible UCST‐type transitions in water. Variable‐temperature UV‐vis analysis revealed that the phase transition temperatures (T_pts) were dependent on the main‐chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2469–2480     

Synthesis of well‐defined photoresist materials by SET‐LRP

Single electron transfer‐living radical polymerization (SET‐LRP) provides an excellent tool for the straightforward synthesis of well‐defined macromolecules. Heterogeneous Cu(0)‐ catalysis is employed to synthesize a novel photoresist material with high control over the molecular architecture. Poly(γ‐butyrolactone methacrylate)‐co‐(methyladamantly methacrylate) was synthesized. Kinetic experiments were conducted demonstrating that both monomers, γ‐butyrolactone methacrylate (GBLMA) and methyl adamantly methacrylate (MAMA), are successfully homopolymerized. In both cases polymerization kinetic is of first order and the molecular weights increase linearly with conversion. The choice of a proper solvent was decisive for the SET‐LRP process and organic solvent mixtures were found to be most suitable. Also, the kinetic of the copolymerization of GBLMA and MAMA was investigated. Following first order kinetics in overall monomer consumption and exhibiting a linear relationship between molecular weights and conversion a “living” process was established. This allowed for the straightforward synthesis of well‐defined photoresist polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2251–2255, 2010     

Investigation on thermoresponsive behavior of biodegradable poly(γ‐glutamic acid)‐graft‐L‐phenylalanine ethyl ester

The thermosensitivity of biodegradable and non‐toxic amphiphilic polymer derived from a naturally occurring polypeptide and a derivative of amino acid was first reported. The amphiphilic polymer consisted of poly(γ‐glutamic acid) (γ‐PGA) as a hydrophilic backbone, and L ‐phenylalanine ethyl ester (L ‐PAE) as a hydrophobic branch. Poly(γ‐glutamic acid)‐graft‐L ‐phenylalanine (γ‐PGA‐graft‐L ‐PAE) with grafting degrees of 7–49% were prepared by varying the content of a water‐soluble carbodiimide (WSC). γ‐PGA‐graft‐L ‐PAE with a grafting degree of 49% exhibited thermoresponsive phase transition behavior in an aqueous solution at around 80°C. The copolymers with grafting degrees in the range of 30–49% showed thermoresponsive properties in NaCl solution. A clouding temperature (T_cloud) could be adjusted by changing the polymer concentration and/or NaCl concentration. The thermoresponsive behavior was reversible. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Acid‐promoted double ring‐opening reaction of bicyclobis (γ‐butyrolactone) with alcohol and its application to polyester synthesis

Bicyclobis(γ‐butyrolactone) (BBL) bearing methyl group 1a reacted with benzyl alcohol (BnOH) in the presence of p‐toluenesulfonic acid (p‐TsOH) through the double ring‐opening of the bislactone structure to afford the corresponding adduct 2a bearing carboxyl group. The resulting carboxyl group underwent condensation with BnOH to afford the corresponding diester 3a . The second step was quite slow at ambient temperature; however, it was efficiently accelerated by elevating temperature to 120 °C or performing under reduced pressure at 80 °C to afford 3a in an excellent yield. Based on these results, the reaction of 1a with xylene‐α,α‐diol (XyD) was carried out in chlorobenzene at 120 °C to obtain the corresponding polyester bearing ketone group in the side chain. The condensation reaction in the second step was effectively promoted by simultaneous removal of water under reduced pressure. BBLs 1b and 1c bearing reactive groups, isopropenyl and chloromethyl, respectively, were also employed as monomers efficiently. Their reactions with XyD gave the corresponding reactive polyesters bearing methacryloyl and chloroacetyl moieties, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of backbone thermo and pH dual‐responsive hyperbranched poly(amine‐ether)s through proton‐transfer polymerization

Stimuli‐responsive hyperbranched polymers have attracted great attention in recent years because of their wide applications in biomedicine. Through proton‐transfer polymerization of triethanolamine and 1,2,7,8‐diepoxyoctane with the help of potassium hydride, a series of novel backbone thermo and pH dual‐responsive hyperbranched poly(amine‐ether)s were prepared successfully in one‐pot. The degrees of branching of the resulting polymers were at 0.40–0.49. Turbidity measurements revealed that hyperbranched poly(amine‐ether)s exhibited thermo and pH dual‐responsive properties in water. Importantly, these responsivities could be readily adjusted by changing the polymer composition as well as the polymer concentration in aqueous solution. Moreover, in vitro evaluation demonstrated that hyperbranched poly(amine‐ether)s showed low cytotoxicity and efficient cell internalization against NIH 3T3 cell lines. These results suggest that these backbone thermo and pH dual‐responsive hyperbranched poly(amine‐ether)s are promising materials for biomedicine. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of degradable hyperbranched poly(2‐ethyl‐2‐oxazoline)

Hyperbranched poly(2‐ethyl‐2‐oxazoline) was synthesized by a combination of cationic ring‐opening polymerization and the oxidation of thiol to disulfide groups. A three‐arm star poly(2‐ethyl‐2‐oxazoline) (PEtOx) was first synthesized using 1,3,5‐tris(bromomethyl) benzene as an initiator. The star PEtOx was end‐capped with potassium ethyl xanthate. Similarly, a linear PEtOx was synthesized and end‐capped with potassium ethyl xanthate using benzyl bromide as an initiator. Hyperbranched PEtOx was then obtained by in situ cleaving and subsequent oxidation of the star PEtOx and linear PEtOx mixture with n‐butylamine as both a cleaving agent and a base in tetrahydrofuran. The linear PEtOx was used to prevent the formation of gel. The hyperbranched PEtOx can be cleaved with dithiothreitol to trithiol and monothiol polymer. The hyperbranched PEtOx shows no remaining thiols using Ellman's assay. The resulting hyperbranched PEtOx was hydrolyzed to a novel hyperbranched polyethyleneimine with degradable disulfide linkages. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2030–2037     

γ‐Butyrolactone Copolymerization with the Well‐Documented Polymer Drug Carrier Poly(ethylene oxide)‐block‐poly(ε‐caprolactone) to Fine‐Tune Its Biorelevant Properties

Polymeric drug carriers exhibit excellent properties that advance drug delivery systems. In particular, carriers based on poly(ethylene oxide)‐block‐poly(ε‐caprolactone) are very useful in pharmacokinetics. In addition to their proven biocompatibility, there are several requirements for the efficacy of the polymeric drug carriers after internalization, e.g., nanoparticle behavior, cellular uptake, the rate of degradation, and cellular localization. The introduction of γ‐butyrolactone units into the hydrophobic block enables the tuning of the abovementioned properties over a wide range. In this study, a relatively high content of γ‐butyrolactone units with a reasonable yield of ≈60% is achieved by anionic ring‐opening copolymerization using 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene as a very efficient catalyst in the nonpolar environment of toluene with an incorporated γ‐butyrolactone content of ≈30%. The content of γ‐butyrolactone units can be easily modulated according to the feed ratio of the monomers. This method enables control over the rate of degradation so that when the content of γ‐butyrolactone increases, the rate of degradation increases. These findings broaden the application possibilities of polyester‐polyether‐based nanoparticles for biomedical applications, such as drug delivery systems.     

Convenient synthesis of poly(γ‐benzyl‐L‐glutamate) from activated urethane derivatives of γ‐benzyl‐L‐glutamate

A series of activated urethane‐type derivatives of γ‐benzyl‐L ‐glutamate were synthesized, and their potential as monomers for polypeptide synthesis was investigated. The derivatives of the focus of this work were a series of N‐aryloxycarbonyl‐γ‐benzyl‐L ‐glutamate 1 , of which aryl groups were phenyl, 4‐chlorophenyl, and 4‐nitrophenyl. These urethanes 1 were reactive in polar solvents such as dimethylsulfoxide, N,N‐dimethylformamide (DMF), and N,N‐dimethylacetamide (DMAc), and were efficiently converted into poly(γ‐benzyl‐L ‐glutamate) (poly(BLG)) under mild conditions; at 60 °C without addition of any catalyst. Among the three urethanes, that having 4‐nitrophenoxycarbonyl group 1c was the most reactive to give poly(BLG) efficiently, as was expected from the highly electron deficient nature of the nitrophenoxycarbonyl group. On the other hand, the urethane 1a having phenoxycarbonyl group was also efficiently converted into poly(BLG), in spite of the intrinsically less electrophilicity of the phenoxycarbonyl group. In addition, the successful formation of poly(BLG) by the reaction of 1a favored its diluted concentration (0.1 M) much more than 2.0 M, the optimum initial concentration for 1c . ¹H NMR spectroscopic analyses of the reactions in situ revealed that the predominant pathway from 1 to poly(BLG) involved the intramolecular cyclization of 1 into the corresponding N‐carboxyanhydride, with release of phenol and its successive ring‐opening polymerization with release of carbon dioxide. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2649–2657, 2008     

One‐pot inimer promoted ROCP synthesis of branched copolyesters using α‐hydroxy‐γ‐butyrolactone as the branching reagent

An array of branched poly(?‐caprolactone)s was successfully synthesized using an one‐pot inimer promoted ring‐opening multibranching copolymerization (ROCP) reaction. The biorenewable, commercially available yet unexploited comonomer and initiator 2‐hydroxy‐γ‐butyrolactone was chosen as the inimer to extend the use of 5‐membered lactones to branched structures and simultaneously avoiding the typical tedious work involved in the inimer preparation. Reactions were carried out both in bulk and in solution using stannous octoate (Sn(Oct)₂) as the catalyst. Polymerizations with inimer equivalents varying from 0.01 to 0.2 were conducted which resulted in polymers with a degree of branching ranging from 0.049 to 0.124. Detailed ROCP kinetics of different inimer systems were compared to illustrate the branch formation mechanism. The resulting polymer structures were confirmed by ¹H, ¹³C, and ₁H‐₁₃C HSQC NMR and SEC (RI detector and triple detectors). The thermal properties of polymers with different degree of branching were investigated by DSC, confirming the branch formation. Through this work, we have extended the current use of the non‐homopolymerizable γ‐butyrolactone to the branched polymers and thoroughly examined its behaviors in ROCP. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1908–1918     

Synthesis and UCST‐type phase behavior of OEGylated poly(γ‐benzyl‐l‐glutamate) in organic media

A series of OEGylated poly(γ‐benzyl‐l ‐glutamate) with different oligo‐ethylene‐glycol side‐chain length, molecular weight (MW = 8.4 × 10³ to 13.5 × 10⁴) and narrow molecular weight distribution (PDI = 1.12–1.19) can be readily prepared from triethylamine initiated ring‐opening polymerization of OEGylated γ‐benzyl‐l ‐glutamic acid based N‐carboxyanhydride. FTIR analysis revealed that the polymers adopted α‐helical conformation in the solid‐state. While they showed poor solubility in water, they exhibited a reversible upper critical solution temperature (UCST)‐type phase behavior in various alcoholic organic solvents (i.e., methanol, ethanol, 1‐propanol, 1‐butanol, 1‐pentanol, and isopropanol). Variable‐temperature UV–vis analysis revealed that the UCST‐type transition temperatures (T_pts) of the resulting polymers were highly dependent on the type of solvent, polymer concentration, side‐ and main‐chain length. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1348‐1356     

Universal Soluble Polymer Supports with Precisely Controlled Loading Capacity for Sequence‐Defined Oligomer Synthesis

Soluble supports, with optimal molecular structures for iterative oligomer synthesis, were prepared by atom transfer radical copolymerization of styrene with Fmoc‐amino ethyl methacrylate. Size exclusion chromatography and nuclear magnetic resonance indicated formation of copolymers with controlled chain lengths, chain ends, dispersity, and comonomer compositions. These polymers were afterward subjected to two subsequent modifications steps: (a) the debromination of their ω‐chain ends via a tributyltin hydride treatment and (b) the removal of the Fmoc‐protecting groups in acidic conditions, thus leading to bromine‐free copolymers with a precise primary amine loading capacity. These universal amine‐containing precursors were then derived into a variety of functional supports. A glycine‐loaded Wang‐type soluble polystyrene support was prepared in two steps and tested for peptide synthesis as well as for the preparation of digital oligo(alkoxyamine amide)s. In both cases, it was possible to obtain uniform sequence‐defined oligomers as evidenced by electrospray ionization tandem mass spectrometry. However, each type of oligomer required specific experimental conditions and therefore soluble supports with an adapted loading capacity for optimal synthesis. Furthermore, the amine‐containing universal precursors were also transformed into soluble supports for iterative phosphoramidite chemistry. A support was specifically conceived for the iterative synthesis of abiotic digital oligo(phosphodiester)s and another one was designed for oligonucleotide synthesis. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 403–410     

Designing of dipeptide‐based oligoconjugates as potential carrier for drug delivery. Pyroglutamil‐S‐glutamic acid bisoligo‐3‐hydroxybutyrates

In the present article, we describe the synthesis and characterization of conjugates based on pyroglutamyl‐S‐glutamic acid and bisoligo‐[R,S]‐3‐hydroxybutyrates (PyGlu‐S_‐Glu_bisOHB) using anionic ring opening polymerization of β‐butyrolactone with a dipeptide bearing two carboxylate groups as potassium salt. The results indicated that the above‐mentioned reaction is accompanied of oligomerization of β‐butyrolactone yielding (3‐hydroxybutyrates) oligomers with crotonate and carboxyl end groups. We report also the end group analysis of the synthesized conjugates using electrospray ionization tandem mass spectrometry (ESI‐MS), the latter confirmed the presence of a mixture of dipeptide conjugate with β‐butyrolactone oligomer chain and β‐butyrolactone homopolymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4103–4111, 2008     

Facile Synthesis of 5‐Hexyl‐4‐methyl‐γ‐butyrolactone via Nef Reaction as a Key Step

A racemic cis/trans mixture of 5‐hexyl‐4‐methyl‐γ‐butyrolactone was easily synthesized from 1‐iodoheptane in four steps with inexpensive and readily available reagents. Our new synthesis method can be potentially employed for mass production of the 4‐methyl‐5‐hexyl‐γ‐butyrolactone as well as other poly‐alkyl substituted γ‐butyrolactones.     

Determination of lipophilicity of γ‐butyrolactone derivatives with anticonvulsant and analgesic activity using micellar electrokinetic chromatography

The lipophilicity of a library of 30 derivatives of dihydrofuran‐2(3H)‐one (γ‐butyrolactone) was determined by MEKC. Calibration curve prepared for ten reference drugs enabled to calculate partition coefficient (log P) for novel compounds. The results of MEKC analysis were compared with lipophilicity coefficients determined by RP‐TLC (R_M0) and computational (Mlog P, Clog P) methods. Good correlation was observed between the results obtained by both experimental methods: the MEKC parameters log k and relative lipophilicity R_MO. The relationship between determined log P values and results of the computational prediction was weaker. Analysis of the relationship between lipophilicity and anticonvulsant activity showed statistically significant differences between mean values of log P coefficients for group of active (2.18) and inactive (1.51) compounds in the maximal electroshock test.     

Synthesis and chemical modification of hyperbranched polyethers with terminal hydroxy groups by the anionic ring‐opening polymerization of 3‐alkyl‐3‐hydroxymethyl oxetanes

The anionic ring‐opening polymerization of oxetanes containing hydroxyl groups was carried out with potassium tert‐butoxide as an initiator in the presence of 18‐crown‐6‐ether in N‐methylpyrrolidinone at 180 °C; it yielded corresponding multifunctional hyperbranched polymers: poly(3‐ethyl‐3‐hydroxymethyloxetane)s, with number‐average molecular weights of 2200–4100 in 83–95% yields, and poly(3‐methyl‐3‐hydroxymethyloxetane)s, with number‐average molecular weights of 4600–5200 in 70–95% yields. The synthesized poly(3‐ethyl‐3‐hydroxymethyloxetane)s and poly(3‐methyl‐3‐hydroxymethyloxetane)s were hyperbranched polyethers containing an oxetane moiety and many hydroxy groups at the ends. The postpolymerization of poly(3‐ethyl‐3‐hydroxymethyloxetane)s was performed in the presence of potassium tert‐butoxide and 18‐crown‐6‐ether in N‐methylpyrrolidinone at 180 °C; it yielded corresponding polymers with higher molecular weights in good yields. The cationic polymerization of poly(3‐ethyl‐3‐hydroxymethyloxetane) derivatives was carried out with boron trifluoride etherate as an initiator and was followed by alkaline hydrolysis; this yielded a new branched polymer, a poly(hyperbranched polyether), with many pendant hydroxy groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3739–3750, 2004     

Synthesis and characterization of hyperbranched‐poly(siloxysilane)‐based polymeric photoinitiators

Three UV‐sensitive, hyperbranched‐poly(siloxysilane)‐based polymeric photoinitiators, bearing an alkyl phenone moiety linked to the surface of the hyperbranched polymer, were synthesized via the hydrosilylation of hyperbranched poly(siloxysilane) and modified UV‐sensitive compounds. Hyperbranched poly(siloxysilane) was prepared via the polyhydrosilylation of the AB₂‐type monomer methylvinyldichlorosilane. The chemical structures of the polymeric photoinitiators were characterized with ¹H, ¹³C, and ²⁹Si NMR, elemental analysis, Fourier transform infrared, differential scanning calorimetry, UV spectrophotometry, and thermogravimetric analysis. The UV‐curing behaviors of the blends of the hyperbranched polymeric photoinitiators with UV‐curable epoxy acrylate (EA) resin were determined by Fourier transform infrared, and the results showed that the initiation efficiency of the polymeric photoinitiators was excellent and that the thermostability of the EA/polymeric photoinitiator curing systems was higher than that of the EA/photoinitiators. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3261–3270, 2006     

Cyclodextrin‐overhanging hyperbranched core‐double‐shell miktoarm architectures: Synthesis and gradient stimuli‐responsive properties

We report the synthesis and gradient stimuli‐responsive properties of cyclodextrin‐overhanging hyperbranched core‐double‐shell miktoarm architectures. A ionic hyperbranched poly(β‐cyclodextrin) (β‐CD) core was firstly synthesized via a convenient “A₂+B₃” approach. Double‐layered shell architectures, composed of poly(N‐isopropyl acrylamide) (PNIPAm) and poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) miktoarms as the outermost shell linked to poly(N,N‐diethylaminoethyl methacrylate) (PDEAEMA) homoarms which form the inner shell, were obtained by a sequential atom transfer radical polymerization (ATRP) and parallel click chemistry from the modified hyperbranched poly(β‐CD) macroinitiator. The combined characterization by ¹H NMR, ¹³C NMR, ¹H‐²⁹Si heteronuclear multiple‐bond correlation (HMBC), FTIR and size exclusion chromatography/multiangle laser light scattering (SEC/MALLS) confirms the remarkable hyperbranched poly(β‐CD) core and double‐shell miktoarm architectures. The gradient triple‐stimuli‐responsive properties of hyperbranched core‐double‐shell miktoarm architectures and the corresponding mechanisms were investigated by UV–vis spectrophotometer and dynamic light scattering (DLS). Results show that this polymer possesses three‐stage phase transition behaviors. The first‐stage phase transition comes from the deprotonation of PDEAEMA segments at pH 9–10 aqueous solution under room temperature. The confined coil‐globule conformation transition of PNIPAm and PDMAEMA arms gives rise to the second‐stage hysteretic cophase transition between 38 and 44 °C at pH 10. The third‐stage phase transition occurs above 44 °C at pH = 10 attributed to the confined secondary conformation transition of partial PDMAEMA segments. This cyclodextrin‐overhanging hyperbranched core‐double‐shell miktoarm architectures are expected to solve the problems of inadequate functionalities from core layer and lacking multiresponsiveness for shell layers existing in the dendritic core‐multishell architectures. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and radical polymerization of methacrylate endowed with bicyclobis(γ‐butyrolactone) moiety through methylene linker

A series of methacrylates bearing bicyclobis(γ‐butyrolactone) (BBL) moiety were synthesized and radically polymerized to afford the corresponding poly(methacrylate)s bearing BBL moiety in the side chain, with expecting that the high polarity and rigidity of BBL would be inherited by the polymers. The resulting polymers were soluble in polar aprotic solvents such as dimethyl sulfoxide and N,N‐dimethylformamide because of the high polarity of the BBL moiety. The glass transition temperatures (T_g) of the polymers depended on the length of methylene linker that tethered the methacrylate and BBL moieties, making the use of shorter linkers lead to higher T_gs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2462–2468