Hydroxyl‐terminated hyperbranched aromatic poly(ether‐ester)s: Synthesis,characterization, end‐group modification,and optical properties

Novel AB₂‐type monomers such as 3,5‐bis(4‐methylolphenoxy)benzoic acid ( monomer 1 ), methyl 3,5‐bis(4‐methylolphenoxy) benzoate ( monomer 2 ), and 3,5‐bis(4‐methylolphenoxy)benzoyl chloride ( monomer 3 ) were synthesized. Solution polymerization and melt self‐polycondensation of these monomers yielded hydroxyl‐terminated hyperbranched aromatic poly(ether‐ester)s. The structure of these polymers was established using FTIR and ¹H NMR spectroscopy. The molecular weights (M_w) of the polymers were found to vary from 2.0 × 10³ to 1.49 × 10⁴ depending on the polymerization techniques and the experimental conditions used. Suitable model compounds that mimic exactly the dendritic, linear, and terminal units present in the hyperbranched polymer were synthesized for the calculation of degree of branching (DB) and the values ranged from 52 to 93%. The thermal stability of the polymers was evaluated by thermogravimetric analysis, which showed no virtual weight loss up to 200 °C. The inherent viscosities of the polymers in DMF ranged from 0.010 to 0.120 dL/g. End‐group modification of the hyperbranched polymer was carried out with phenyl isocyanate, 4‐(decyloxy)benzoic acid and methyl red dye. The end‐capping groups were found to change the thermal properties of the polymers such as T_g. The optical properties of hyperbranched polymer and the dye‐capped hyperbranched polymer were investigated using ultraviolet‐absorption and fluorescence spectroscopy. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5414–5430, 2008     

β‐Cyclodextrin polymer brushes based on hyperbranched polycarbosilane: Synthesis and characterization

In this article, our main goal is to combine hyperbranched polymer with β‐cyclodextrin (β‐CD) to establish a novel functional polymer species with core‐shell structure and supramolecular system for further application in inclusion technologies and the complex drugs delivery system. Therefore, two β‐CD polymer brushes based on hyperbranched polycarbosilane (HBP) as a hydrophobic core and poly(N,N‐dimethylaminoethyl methacrylate) (PDMA) carrying β‐CD units as a hydrophilic shell were synthesized. Hyperbranched polycarbosilane macroinitiator carrying ? Cl groups (HBP‐Cl) was also prepared by using 1,1,3,3‐tetrmethyldisiloxane, allyl alcohol, and chloroacetyl chloride as reagents. The molecular structures of HBP‐Cl macroinitiator and β‐CD polymer brushes were characterized by Fourier transform infrared spectroscopy (FTIR), ¹H nuclear magnetic resonance (¹H NMR), ¹³C nuclear magnetic resonance (¹³C NMR) spectroscopies, size exclusion chromatography/multi‐angle laser light scattering (SEC/MALLS) and laser particle size analyzer. The results indicate that the grafted chain length of two β‐CD polymer brushes can be controlled by changing the feed ratio. Differential scanning calorimetry (DSC) results show that two β‐CD polymer brushes have two glass transition temperatures (T_gs) from a hydrophobic core part and a hydrophilic shell part, respectively, and the T_g from PDMA is higher than that of HBP‐g‐PDMA. Thermalgravimetric analyzer (TGA) analysis indicates that the thermostability of two β‐CD polymer brushes is higher than that of HBP, but is lower than that of HBP‐g‐PDMA. Using phenolphthalein (PP) as a guest molecule, molecular inclusion behaviors for two β‐CD polymer brushes were studied. It reveals that two β‐CD polymer brushes possess molecular inclusion capability in PP buffer solution with a fixed concentration. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5036–5052, 2008     

Water‐soluble,thermoresponsive, hyperbranched copolymers based on PEG‐methacrylates: Synthesis,characterization, and LCST behavior

A series of water‐soluble thermoresponsive hyperbranched copoly(oligoethylene glycol)s were synthesized by copolymerization of di(ethylene glycol) methacrylate (DEG‐MA) and oligo(ethylene glycol) methacrylate (OEG‐MA, M_w = 475 g/mol), with ethylene glycol dimethacrylate (EGD‐MA) used as the crosslinker, via reversible addition fragmentation chain transfer polymerization. Polymers were characterized by size exclusion chromatography and nuclear magnetic resonance analyses. According to the monomer composition, that is, the ratio of OEG‐MA: DEG‐MA: EGD‐MA, the lower critical solution temperature (LCST) could be tuned from 25 °C to 90 °C. The thermoresponsive properties of these hyperbranched copolymers were studied carefully and compared with their linear analogs. It was found that molecular architecture influences thermoresponsive behavior, with a decrease of around 5–10 °C in the LCST of the hyperbranched polymers compared with the LCST of linear chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2783–2792, 2010     

Synthesis of dendritic terpolymers consisting of polystyrene,polybutadiene, and polyisoprene with different isomerisms

We report the synthesis of two 2nd generation dendritic terpolymers consisting of poly(butadiene) (PB) of 1,4 geometric isomerism, poly(isoprene) (PI) enriched in 3,4 geometric isomerism (at least 55% PI_3,4) and polystyrene (PS). The main focus of this work was the synthesis of well‐defined dendritic terpolymers exhibiting high levels of molecular and compositional homogeneity. The preparation of these materials was achieved via anionic polymerization techniques in combination with chlorosilane linking chemistry. The molecular characterization of the intermediate products and the final dendritic materials was accomplished via gel permeation chromatography, membrane osmometry, differential scanning calorimetry, and ¹H‐nuclear magnetic resonance spectroscopy, leading to the conclusion that they can be considered model polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1567–1574, 2009     

Tuning the optical properties of hyperbranched polymers through the modification of the end groups

Dye‐capped, hyperbranched, conjugated polymers were prepared by the modification of the peripheral bromo end groups of the hyperbranched polymer core with a palladium‐catalyzed Suzuki–Miyaura cross‐coupling reaction. The dye‐modified, hyperbranched polymers had high molecular weights and displayed good solubility in common organic solvents such as tetrahydrofuran, toluene, and chloroform. The structure of the dye‐modified, hyperbranched polymers was characterized by ¹H and ¹³C NMR and elemental analysis. The thermal properties of five kinds of hyperbranched polymers were investigated with thermogravimetric analysis and differential scanning calorimetry. The optical properties of the dye‐capped, hyperbranched polymers were investigated with ultraviolet‐absorption and fluorescence spectroscopy. The hyperbranched structure could effectively reduce the aggregation of the peripheral dyes. The emission colors of the hyperbranched polymers could be easily tuned by end‐group modification. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 111–124, 2007     

Hyperbranched block copolymer from AB2 macromonomer: Synthesis and its reaction‐induced microphase separation in epoxy thermosets

In this contribution, we reported the synthesis of a hyperbranched block copolymer composed of poly(ε‐caprolactone) (PCL) and polystyrene (PS) subchains. Toward this end, we first synthesized an α‐alkynyl‐ and ω,ω′‐diazido‐terminated PCL‐b‐(PS)₂ macromonomer via the combination of ring‐opening polymerization and atom transfer radical polymerization. By the use of this AB₂ macromonomer, the hyperbranched block copolymer (h‐[PCL‐b‐(PS)₂]) was synthesized via a copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition (i.e., click reaction) polymerization. The hyperbranched block copolymer was characterized by means of ¹H nuclear magnetic resonance spectroscopy and gel permeation chromatography. Both differential scanning calorimetry and atomic force microscopy showed that the hyperbranched block copolymer was microphase‐separated in bulk. While this hyperbranched block copolymer was incorporated into epoxy, the nanostructured thermosets were successfully obtained; the formation of the nanophases in epoxy followed reaction‐induced microphase separation mechanism as evidenced by atomic force microscopy, small angle X‐ray scattering, and dynamic mechanical thermal analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 368–380     

Photoactive,liquid‐crystalline,hyperbranched benzylidene polyesters: Synthesis and characterization

A novel photoactive, liquid‐crystalline, hyperbranched benzylidene polyester (PAHBP) was synthesized from a dilute solution of an A₂ photoactive monomer [bis(4‐hydroxybenzylidene)‐4‐phenyl cyclohexanone] and a B₃ monomer (1,3,5‐benzene tricarboxylic acid chloride) by the solution polycondensation method in the presence of pyridine as a condensing agent. PAHBP was thoroughly characterized by Fourier transform infrared, ¹H and ¹³C NMR, ultraviolet–visible spectrometry, and gel permeation chromatography. The inherent viscosity of the polymer was 0.35 dL/g in tetrahydrofuran. The degree of branching was 0.53, which confirmed the branched architecture of the polymer. Furthermore, thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy were used to examine the thermal stability and thermotropic liquid‐crystalline properties of the hyperbranched polyester. The polymer exhibited a nematic mesophase over a wide range of temperatures. The photoreactivity of PAHBP was studied by photolysis under ultraviolet light. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 53–61, 2006     

Theoretical consideration of the molecular mass distribution of starlike polymers formed by attachment of linear polymers to dendritic cores

Star‐shaped polymers can be synthesized by condensation of linear polymers to dendritic cores. The distribution of molecular masses of such hybrid star polymers and the factors influencing it have been investigated by calculations based on population balance equations and Laplace transformations. Moreover, the expressions for numerical calculations of molecular mass distributions have been derived for both Poisson and Schultz–Zimm types of initial molecular mass distributions. According to the calculation results, the molecular mass distribution of the star polymers is strongly dependent on the distribution of the length of linear polymers. Beyond this, the molecular mass development is affected by several parameters that describe the reaction degree of dendritic cores, thus, by the fraction of all functional groups of dendritic cores involved in grafting, denoted by p; the average branching degree of one starlike molecule, represented by ρ; or the fraction of dendritic molecules becoming the cores of star polymers, expressed by p/ρ, provided the star molecule contains only one core. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2751–2758, 2001     

Systematic investigation of functional core variation within hyperbranched polyglycerols

A novel series of hyperbranched polyether polyols with various n‐alkyl amine cores (mono‐ and bifunctional) and photoactive cores (benzylamine and 1‐naphthylmethylamine) have been prepared. Polymerization of glycidol was carried out in two ways, starting directly from primary amine initiators and from bisglycidolized amine initiators. NMR spectroscopy and size exclusion chromatography (SEC) showed good control over the molecular weights only, when bisglycidolized amines were used. Molecular weights and polydispersity of the hyperbranched polyglycerols prepared with these initiator‐cores were in the range of 1600 to 8400 g/mol and of 1.5 to 2.5, respectively. MALDI‐ToF mass spectrometry confirmed covalent attachment of the functional cores to the hyperbranched polymers. When using the bis‐glycidolized amine‐initiators, only functionally initiated polymers could be observed. In contrast, the direct amine‐initiated polymers always showed the presence of nonfunctionalized PG homopolymer. Steady‐state and time‐resolved fluorescence measurements further support covalent attachment and site isolation of the functional initiators within the hyperbranched structure. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2049–2061, 2008     

The effect of dendritic pendants on the folding of amphiphilic copolymers via supramolecular interactions

The supramolecular folding of amphiphilic heterograft copolymers equipped with dendritic pendants is investigated using a combination of proton nuclear magnetic resonance (¹H NMR) spectroscopy, small‐angle X‐ray scattering, and circular dichroism spectroscopy. Hereto, the linear poly(ethylene glycol) pendants normally used to convey water compatibility are partially substituted with branched analogues. For one set of copolymers, second‐generation polyglycerol dendrons are directly attached to the polymer backbone, while for the other a hydrophilic linker is placed in between. The results show that the branching of the hydrophilic pendants affects the local structure of the folded copolymer but does not influence the overall conformation and single‐chain character of the folded copolymers in solution. All copolymers fold into 4–5 nm single‐chain polymeric nanoparticles with a very compact spherical morphology, independent of the dendritic content of the copolymer. Intriguingly, the incorporation of the dendritic pendants affects the formation of a structured interior even at low incorporation ratios. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 411–421     

Distribution of Dendritic,Terminal and Linear Units and Relationship between Degree of Branching and Molecular Weight of AB2‐Type Hyperbranched Polymer: A 13C‐NMR Study

Degree of branching (DB) of AB₂‐type hyperbranched polymer has been studied using ¹³C‐NMR spectroscopy. For this purpose, a series of hyperbranched polyamides based on 3,5‐bis(4‐aminophenoxy)benzoic acid differing in molecular weight was prepared by adopting a fractional precipitation technique. A model compound mimicking exactly the terminal and dendritic units present in the hyperbranched polymer (HBP) was also synthesized in high yield. ¹³C‐NMR spectra of the polymers and the model compound were recorded under exacting experimental conditions. With the help of ¹³C‐NMR spectrum of model compound and the integration values, peaks for terminal (T) units, dendritic (D) units and linear (L) units present in the HBP have been assigned. The spectra of low molecular weight fractions clearly showed that the linear unit is first formed and then the dendritic unit. Plots of mole fraction of individual unit against molecular weight (M_w) and DB against molecular weight (M_w) are constructed. For the first time, it is found that there is a critical molecular weight (the value calculated is between 3200–3500 for the chosen real system) below, which DB is dependent on molecular weight and above which it becomes independent. A new term T+D/L, which has a maximum value of 20 and minimum of 1, characterizing all AB₂‐type hyperbranched polymers in general, has been introduced.     

Synthesis and characterization of hyperbranched polyesters and polyurethane coatings

Polyurethane (PU) coatings are widely used for variety of high‐performance applications in today's coating technology. The emerging hyperbranched polymers having three‐dimensional morphology have opened a new avenue to tailor the architecture of PU coatings. The methodology followed here is based on preparation of PU coatings from hyperbranched polyester. Initially, different hyperbranched polyester polyols (HPs) were synthesized by varying the hydroxyl‐terminated precursors that is, pentaerythritol, trimethylol propane or glycerol and keeping the diacid that is, adipic acid quantity constant at various mole ratios of 1:0.6, 1:0.8, 1:0.9, and 1:1, respectively. The obtained HPs were characterized by nuclear magnetic resonance (NMR) spectroscopy, matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF)‐mass spectrometry, and Fourier transform‐infrared (FTIR) spectroscopy. The degree of branching and the quantity of different structural units present in the various HPs were calculated by integrating the quaternary carbon and carbonyl zone in ¹³C NMR spectroscopy. The extent of condensation in different HPs was also calculated from ¹H NMR spectra. Later on, NCO‐terminated PU prepolymers (NCO‐PU) were synthesized by reacting HPs with isophorone diisocyanate (IPDI) at NCO/OH ratio of 1.6:1. In the third step, the excess NCO content in the NCO‐capped PU prepolymers were reacted with atmospheric moisture and hyperbranched polyurethane (HPU) coatings were formed. The coating films were analyzed by FTIR and dynamic mechanical thermal analysis instruments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2673–2688, 2007     

Multiarm star polymers with a thermally cleavable core: A “grafting‐from” approach paves the way

Thermally cleavable multiarm star polymers containing thermo‐reversible furan–maleimide cycloadduct‐based core were synthesized using dendritic macroinitiators. Peripheries of dendritic macroinitiators were modified with bromine containing free radical initiators to obtain multiarm polymers by utilizing atom transfer radical polymerization (ATRP). Cleavage of thus obtained multiarm polymers was achieved via the retro Diels–Alder cycloreversion reaction of the furan–maleimide core at elevated temperatures. As an alternative approach, combination of multiarm polymers containing a furan and maleimide functional group at their core was attempted to realize that the steric bulk does not allow their formation. Hence the “grafting‐from” route using a thermally fragmentable trigger containing multiarm initiators provides a plausible methodology for fabrication of such thermally cleavable multiarm polymeric materials. Syntheses of dendritic initiators, formation of star polymers as well as their fragmentation were followed by proton nuclear magnetic resonance spectroscopy and size exclusion chromatography. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 885–893     

Synthesis and characterization of a novel reactive ladderlike 4,4′‐phenylene ether‐bridged polyvinylsiloxane

A novel soluble, reactive ladderlike 4,4′‐phenylene ether‐bridged polyvinylsiloxane (L) was synthesized successfully for the first time by a stepwise coupling polymerization (SCP) including hydrolysis and polycondensation. The monomer, 4,4′‐bis(vinyldimethoxysilyl)phenylene ether (M), was synthesized by Grignard reaction. The structures of the monomer and the polymer were characterized by infrared spectrometry (IR), nuclear magnetic resonance (¹H NMR, ¹³C NMR, ²⁹Si NMR), mass spectrometry (MS), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and gel permeation chromatography (GPC). It is proposed from the characterization data that the polymer possesses an ordered ladderlike structure. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2702–2710, 2000     

Radical alternating copolymerization: A strategy for hyperbranched materials

Novel hyperbranched polymers were synthesized in a high yield without gelation through the free‐radical alternating copolymerization of an AB/B′ (allyloxy maleic acid/maleic anhydride) system, in which group B and monomer B′ both could only alternately polymerize with group A. The arm number of the produced highly branched polymers was equal to the product of the linear chain length and the probability of pendent B groups being growing centers. The molecular weight of these novel hyperbranched polymers increased with increasing initiator concentration and prolonged polymerization times. The AB/B′ system, used as described, provides a new general methodology for highly branched and functional polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3074–3085, 2000     

Photoactive liquid crystalline polymers: A comprehensive study of linear and hyperbranched polymers synthesized by A2B2, A2B3, A3B2, and A3B3 approaches

A series of linear and hyperbranched polyester epoxies, with varied structural parameters such as kinked structure and different dendritic architectures, were synthesized by A₂ + B₂, A₂ + B₃, A₃ + B₂, and A₃ + B₃ approaches. The structures of synthesized monomers and polymers were confirmed by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopic techniques. The effect of varied structural parameters on phase behavior and photoresponsive properties was investigated by using differential scanning calorimeter, thermal optical polarized microscope, UV–visible spectroscopy, photoviscosity, and refractive index studies. The transition temperatures of hyperbranched polymers were higher than that of the corresponding linear analogues. All the polymers showed nematic phase (nematic droplets) over a broad temperature range. The effect of kinked structural unit on photoresponsive property is less in both linear and hyperbranched architectures. Although the effect of architectural nature is highly considerable within the hyperbranched architectures, the polymer (HPE–33) synthesized by A₃ + B₃ approach showed highest rate of photocrosslinking, followed by HPE–I 32; HPE–T 32, and HPE–23, which were synthesized by A₃ + B₂ and A₂ + B₃ approaches, respectively. The findings in photoresponsive properties were further supported by molecular modeling studies. Substantial variation of refractive index (0.015–0.024) indicates that these polymers could be used for optical recording. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A facile strategy for synthesis of α,α′‐heterobifunctionalized poly (ε‐caprolactones) and poly (methyl methacrylate)s containing “clickable” aldehyde and allyloxy functional groups using initiator approach

Two new initiators, namely, 4‐(4‐(2‐(4‐(allyloxy) phenyl)‐5‐hydroxypentane 2‐yl) phenoxy)benzaldehyde and 4‐(4‐(allyloxy) phenyl)‐4‐(4‐(4‐formylphenoxy) phenyl) pentyl 2‐bromo‐2‐methyl propanoate containing “clickable” hetero‐functionalities namely aldehyde and allyloxy were synthesized starting from commercially available 4,4′‐bis(4‐hydroxyphenyl) pentanoic acid. These initiators were utilized, respectively, for ring opening polymerization of ε‐caprolactone and atom transfer radical polymerization of methyl methacrylate. Well‐defined α‐aldehyde, α′‐allyloxy heterobifunctionalized poly(ε‐caprolactones) (M_n,GPC: 5900–29,000, PDI: 1.26–1.43) and poly(methyl methacrylate)s (M_n,GPC: 5300–28800, PDI: 1.19–1.25) were synthesized. The kinetic study of methyl methacrylate polymerization demonstrated controlled polymerization behavior. The presence of aldehyde and allyloxy functionality on polymers was confirmed by ¹H NMR spectroscopy. Aldehyde‐aminooxy and thiol‐ene metal‐free double click strategy was used to demonstrate reactivity of functional groups on polymers. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis of novel boron‐containing epoxy–novolac resins and properties of cured products

Epoxy–novolac resins were synthesized by modifying a commercial novolac resin with epichlorohydrin. These epoxy–novolac resins were characterized and further modified with different contents of bis(benzo‐1,3,2‐dioxa‐borolanyl)oxide or bis(4,4,5,5‐tetramethyl‐1,3,2‐dioxa‐borolanyl)oxide. The boron‐containing epoxy–novolac resins were autocatalytically crosslinked or crosslinked with BF₃MEA and their thermal stability and flame retardancy were determined by thermogravimetric analysis and limiting oxygen index (LOI) values. These LOI values for the bis(benzo‐1,3,2‐dioxa‐borolanyl)oxide derivatives were higher than the boron‐free novolac resins, which shows the benefit of the presence of boron. To test the role of boron in the enhancement of flammability, scanning electronic microscopy and energy‐dispersive X‐ray spectroscopy images were made. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6332–6344, 2006     

Hyperbranched Polyfluorinated benzyl ether polymers: Mechanism,kinetics, and optimization

Highly fluorinated, hyperbranched polymers were synthesized from the polycondensation of AB₂ monomers, 3,5‐bis[(pentafluorobenzyl)oxy]benzyl alcohol and 3,5‐bis[(pentafluorobenzyl)‐oxy]phenol with potassium carbonate base, and 18‐crown‐6 phase transfer agent in a variety of polar aprotic solvents. The regioselectivity of the polymerization was optimized and was found to be temperature dependent. The new polymerization technique produced higher molecular weight polymer using safer conditions than earlier methods. The resulting optimization was used to control substitution of oxygen‐bearing nucleophiles along nonactivated fluoroaryl systems in high yield. Water was found to induce side reactions that generate a highly conjugated fluoroaryl phenol with lowered reactivity. The removal of a methylene spacer in the polymer backbone of the hyperbranched polymer produced a polymer with greater thermal stability. The reaction conditions for polymerization were found to be general for nucleophile‐bearing perfluorinated systems. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 985–994     

Synthesis and characterization of star graft copolymers with asymmetric mixed “V‐shaped” side chains via “click” chemistry on a hyperbranched polyglycerol core

The star graft copolymers composed of hyperbranched polyglycerol (HPG) as core and well defined asymmetric mixed “V‐shaped” identical polystyrene (PS) and poly(tert‐butyl acrylate) as side chains were synthesized via the “click” chemistry. The V‐shaped side chain bearing a “clickable” alkyne group at the conjunction point of two blocks was first prepared through the combination of anionic polymerization of styrene (St) and atom transfer radical polymerization of tert‐butyl acrylate (tBA) monomer, and then “click” chemistry was conducted between the alkyne groups on the side chains and azide groups on HPG core. The obtained star graft copolymers and intermediates were characterized by gel permeation chromatography (GPC), GPC equipped with a multiangle laser‐light scattering detector (GPC‐MALLS), nuclear magnetic resonance spectroscopy and fourier transform infrared. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1308–1316, 2009