Synthesis of poly(ɛ-caprolactone-b-isobutylene) diblock copolymer and poly(ɛ-caprolactone-b-isobutylene-b-ɛ-caprolactone) triblock copolymer

Summary Poly(isobutylene-b-ɛ-caprolactone) diblock and poly(ɛ-caprolactone-b-isobutylene-b-ɛ-caprolactone) triblock copolymers have been prepared and characterized. The synthesis involved the living cationic polymerization of IB, followed by capping with 1,1-diphenylethylene or 1,1-p-ditolylethylene and end-quenching with 1-methoxy-1-trimethylsiloxy-2-methyl-propene to yield methoxycarbonyl functional PIB. Hydroxyl end-functional PIB polymers were quantitatively obtained by the subsequent reduction of methoxycarbonyl end-functional PIB with LiAlH₄. The structure of hydroxyl end-functional PIBs was confirmed by ¹H NMR and IR spectroscopy. Poly(ɛ-caprolactone-b-isobutylene) diblock copolymers and poly(ɛ-caprolactone-b-isobutylene-b-ɛ-caprolactone) triblock copolymers were synthesized by the living cationic ring-opening polymerization of ɛ-caprolactone with hydroxyl end-functional PIB as macroinitiator in the presence of HCl•Et₂O via the “activated monomer mechanism”. The block copolymers exhibited close to theoretical M_ns and narrow molecular weight distributions. Received: 30 January 2002/Revised version: 19 February 2002/ Accepted: 19 February 2002     

New polyisobutylene stars XI. Synthesis and characterization of allyl-telechelic octa-arm polyisobutylene stars

The synthesis and characterization of a novel star comprising eight allyl-terminated polyisobutylene (PIB) arms radiating from a calix[8]arene core is described. The synthesis was accomplished by a core-first method, by inducing the living polymerization of isobutylene (IB) by a suitably functionalized calix[8]arene initiator (1) in conjunction with BCl₃-TiCl₄ coinitiators, and terminating the growth of the living PIB^⊕ arms by allyltrimethylsilane. The relative concentrations of BCl₃ and TiCl₄ are critical for the synthesis of well-defined 8-arm stars. Characterization of the products (which included triple detector GPC studies and ¹H NMR spectroscopy) indicated quantitative allylation. A mechanism which summarizes the experimental observations is proposed. Received: 17 July 1997/Revised version: 11 September 1997/Accepted: 19 September 1997     

Scale-up precision synthesis of octa-arm polyisobutylene stars

Summary This paper concerns the scale-up precision synthesis of octa-arm polyisobutylene (PIB) stars. Specifically, we have optimized to the 100–200 g scale the preparation of star polymers consisting of eight PIB arms radiating from a calix[8]arene core. The synthesis strategy involved the use of a calix[8]arene fitted with eight p-C(CH₃)₂OCH₃ groups as the initiator in conjunction with mixed BCl₃/TiCl₄ coinitiators in hexanes/methyl chloride solvent systems at − 80 °C. Various possible side-reactions have been identified and means for their suppression/elimination were developed. Received: 29 December 1999/Revised version: 22 May 2000/Accepted: 22 May 2000     

Synthesis of Poly(cyclohexyl vinyl ether-<Emphasis Type="Italic">b</Emphasis>-isobutylene-<Emphasis Type="Italic">b</Emphasis>-cyclohexyl vinyl ether) Triblock Copolymer by Living Cationic Sequential Copolymerization

Summary The living cationic polymerization of cyclohexyl vinyl ether (CHVE) and sequential block copolymerization of isobutylene with CHVE were carried out by the so-called capping-tuning technique in hexanes/CH₃Cl solvent mixtures at –80 °C. It involves capping the initiator, 2-chloro-2,4,4-trimethylpentane (TMPCl), or the living polyisobutylene (PIB) chain end with 1,1-ditolylethylene in the presence of titanium(IV) (TiCl₄), followed by fine-tuning of the Lewis acidity with the addition of titanium(IV) isopropoxide (Ti(OIp)₄) to match the reactivity of CHVE. Well-defined PCHVE, PIB-b-PCHVE and PCHVE-b-PIB-b-PCHVE with predesigned molecular weights and narrow molecular weight distributions (M_w/M_n<1.1) were thus prepared with [Ti(OIp)₄]/[TiCl₄] ratios of 1.6–1.8. Differential scanning calorimetry of the triblock copolymers showed two T_gs (–62 °C for PIB and 61 °C for PCHVE) suggesting a microphas-separated morphology of the triblock copolymers and the potential use of them as thermoplastic elastomers.     

Electrochemical oxidation of <Emphasis Type="Italic">p</Emphasis>-sulfonated calix[8]arene

The water-soluble p-sulfonated sodium salt of calix[8]arene (III) was synthesized. The product was characterized by FT-IR, NMR and UV–Vis spectra.Then the electrochemical behaviors of p-sulfonated sodium salt of calix[8]arene in NaAc+HAc (pH = 4) buffer solution was studied. In aqueous solution, p-sulfonated calix[8]arene can be oxidized when the potential is more than 0.7 V vs SCE. It was confirmed that the reaction was a two-electron irreversible electrochemical reaction. The transfer coefficient, α, was measured as 0.7. At 25°, the diffusion coefficient of p-sulfonated calix[8]arene was determined as 8.6 × 10⁻⁷ cm² s⁻¹. The diffusion activation energy of p-sulfonated calix[8]arene was 18.9 kJ mol⁻¹ at pH = 4.     

Selective Extraction of Fe3+ Cation by Calixarene-Based Cyclic Ligands

Abstract

The selective liquid-liquid extraction of Fe³⁺ cation from the aqueous phase to the organic phase was carried out by using p-tert-butylcalix[4]arene [L₁], ca-lix[4]arene [L₂], p-nitro-calix[4]arene [L₃], calix[4]arene p-sulfonic acid [L₄], p-(diethylamino)methylcalixt4]arene [L₅], tetramethyl-p-tert-butylcalix[4]arene tet-raketone [L₆], 25,27-dimethyl-26,28-dihydroxy-p-tert-butylcalix[4]arene diketone [L₇], calix[4]arene-bearing dioxime group on the lower rim [L₈], and a monooxime [L₉]. The effect of varying pH upon the extraction ability of calixarenes substituted with electron-donating and electron-withdrawing groups at their p-position was examined. Observed results were compared with those found for unsubstituted calix[4]arene.     

Blends of a thermotropic liquid crystalline polymer and some flexible chain polymers and the determination of the polymer-polymer interaction parameter of the two polymers

Summary Blends of a thermotropic liquid crystalline polymer (LCP) with poly(ether imide) (PEI), poly(ether ether ketone) (PEEK), polysulfone (PSF) and polyarylsulfone (PAS) prepared by screw extrusion have been investigated by differential scanning calorimeter and dynamic mechanical thermal analysis. From the measured glass transition temperature (T_g) and specific heat increment (ΔC_p) at the T_g, it appears that the LCP dissolves more in the PEI- and PEEK-rich phases than does the PEI and PEEK in the LCP-rich phase. From the DSC study of PSF-LCP and PAS-LCP blends, the T_g(PSF) and T_g(PAS) of each blends are almost constant with blend composition. Therefore, it is concluded that PSF and PAS are immiscible with LCP. The polymer-polymer interaction parameter (χ₁₂) and the degree of disorder (y/x₁) of LCP have been investigated using the Flory lattice theory in which the anisotropy of LCP is considered. The χ₁₂ values have been calculated from the T_g data and found to be 0.181 ± 0.004 at 593 K for the PEI-LCP blends and 0.069 ± 0.006 at 623 K for the PEEK-LCP blends. Using the previously presented method, the χ₁₂ and y/x₁ in partially miscible systems have been determined. Received: 6 April 1998/Revised version: 8 June 1998/Accepted: 17 June 1998     

Poly[(styrene-co-p-methylstyrene)-b-isobutylene-b-(styrene-co-p-methylstyrene)] triblock copolymers. 1. Synthesis and characterization

The synthesis of poly(isobutylene) (PIB)-based triblock copolymers having copolymer end blocks containing styrene and p-methylstyrene (pMSt) repeat units was investigated in an attempt to minimize chain-coupling reactions that occur at the 4-position on styrene repeat units during end block polymerization. Model end block copolymerizations using varying feed ratios of styrene and pMSt were conducted, and it was determined by ¹H NMR analysis that the addition of pMSt to the living chain end was favored slightly at low conversion. However, DSC revealed a single T_g that increased with increasing pMSt content verifying the absence of blockiness in the microstructure. Poly[(styrene-co-pMSt)-b-isobutylene-b-(styrene-co-pMSt)] triblock copolymers were synthesized using varying feed ratios of styrene and pMSt. The rate of end block propagation increased with increasing pMSt in the feed, and the end block copolymerizations initiated by PIB displayed longer reaction times and more curvature in their first order plots than did the model end block copolymerizations initiated by TMPCl. This effect was attributed to lower ionization equilibrium constant and higher degree of termination caused by the more non-polar local reaction medium provided by the PIB center blocks in block copolymerization. GPC analysis of the final BCPs revealed a decrease in a high molecular weight peak representing the chain-coupled product as the concentration of pMSt in the feed was increased.     

Molecular composites obtained by polyaniline synthesis in the presence of p‐octasulfonated calixarene macrocycle

Polyaniline (PANI) molecular composites were synthesized by chemical oxidative polymerization of the aniline and aniline dimer, N‐phenyl‐1,4‐phenylendiamine, in the presence of a macrocycle, calix[8]arene p‐octasulfonic acid (C8S), using ammonium peroxidisulfate as oxidant. The macrocycle has acted both as acid dopant and surfactant to obtain processable PANI‐ES. The PANI/calix[8]arene p‐octasulfonic acid composite was also obtained by a simple doping of PANI emeraldine base form with calix[8]arene sulfonic acid. The structure of materials was confirmed by Fourier transform infrared, UV–vis and nuclear magnetic resonance spectroscopy. All synthesized composite materials are amorphous and soluble in chloroform, dimethylsulfoxide, NMP, showing excellent solution‐processing properties combined with electrical conductivity. Cyclic voltammetry evidenced a good electroactivity for the composite films. Dielectric properties (dielectric constant and dielectric losses) were determined and are comparable with those of other PANI/ionic acid polymer composites. Preliminary studies have evidenced a high dielectric constant (10⁴ at 100 Hz) and electrical conductivity of 6 × 10^?3 S/cm for PANI composites. From sulfur elemental analysis of the PANI/calixarene, it results that the content in macrocycle is ～30% (weight). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Poly(styrene-b-isobutylene-b-styrene) block copolymer ionomers (BCPI), and BCPI/silicate nanocomposites. 1. Organic counterion: BCPI sol-gel reaction template

Silicate structures were inserted along the cylindrical polystyrene (PS) domains in an ionomer form of elastomeric poly(styrene-b-isobutylene-b-styrene) tri-block copolymers, via in situ sol-gel reactions. Environmental scanning electron microscopy/energy dispersive X-ray spectroscopy studies indicated that silicate structures do in fact grow within the interior of ca. 0.8 mm thick films rather than forming undesirable silica precipitates on the surface. The combination of a domain-selective swelling solvent (DMAc) and the attachment of large organic counterions (benzyltrimethylammonium) along the styrene blocks facilitated the preferential migration of hydrolyzed Si(OEt)₄ monomers to these ionic domains where the sol-gel reactions are apparently seeded. Differential scanning calorimetry and dynamic mechanical studies indicated that T_g for the polyisobutylene (PIB) phase is essentially unaffected, but the PS phase T_g shifts to higher values with ionomer formation, and to even higher values with subsequent silicate phase insertion. These two methods provide indirect evidence that the silicate component is mainly incorporated in the PS rather than PIB domains. Combined with the results of earlier atomic force microscopy studies that demonstrated that the basic morphology of the unmodified block copolymer is unchanged despite the insertion of a silicate phase, the data presented here reinforce the concept of a robust sol-gel reaction template. Also, the rubbery plateau storage modulus was elevated as a result of ionomer formation and more so after the ionomer was imparted with a silicate phase, which illustrates mechanical reinforcement.     

Synthesis of poly(styrene-b-isobutylene-b-styrene) triblock copolymer by ATRP

Summary A poly(styrene-b-isobutylene-b-styrene) triblock copolymer has been prepared by a two-step process. Polyisobutylene with M_n= 6600 and M_w/M_n= 1.12 functionalized with phenol at both ends was reacted with 2-bromopropionyl chloride to form a macroinitioator for atom transfer radical polymerization (ATRP). The synthesized difunctional PIB macroinitiator was subsequently heated with styrene xylene solution in the second step to 110°C under conditions for ATRP using the copper coordination complex CuBr/bipyridine. Both the macroinitiator and the triblock copolymer were characterized by ¹H NMR and SEC. The triblock copolymer with around 25% polystyrene was found to have a narrow molecular weight distribution of 1.20. Received: 4 October 1998/Revised version: 29 October 1998/Accepted: 3 November 1998     

Synthesis and Polymerization of a Four-Arm Star with Pendent Cyclopentadienyliron Moieties

The synthesis of the title complex was achieved via the reaction of a η⁶-p-dichlorobenzene-η⁵-cyclopentadienyliron cation with an organic four-arm core to produce the tetrairon complex. This tetrairon-containing core was subsequently polymerized via nucleophilic aromatic substitution with various dinucelophiles such as 4,4′-thiobenzenethiol, bisphenol-A, 4,4′-(1-phenylethylidene)bisphenol, 4,4′-biphenol, bis(4-hydroxyphenyl)methane, producing five different cross-linked cationic organoiron polymers. Another cross-linked polymer was produced via direct polymerization of the four-arm organic core with the η⁶-p-dichlorobenzene-η⁵-cyclopentadienyliron cation. Due to the poor solubility of these cross-linked polymers, solid-state ¹³C CPMAS NMR was performed in order to verify that polymerization was successful. Thermogravimetric analysis (TGA) revealed that following the decoordination of the cyclopentadienyliron moieties, the polymers were thermally stable. Differential scanning calorimetry (DSC) showed that the polymers exhibited glass transition temperatures (T _g’s) ranging from 104 to 146°C. This article is dedicated to Professor Ian Manners for his outstanding contribution to the field of metal-containing polymers.     

Calixarenes 30. Calixquinones

Chlorine dioxide and thallium trifluoroacetate are shown to be useful reagents for the preparation of calixquinones. p-H-Calix[4]arene( 1a ),p-H-calix[5]arene ( 1b ), and p-H-calix[6]arene ( 1c ) are oxidized in modest yields by ClO₂ to the fully quinonoid compounds calix[4]tetraquinone ( 2a ), calix[5]pentaquinone ( 2b ), and calix[6]hexaquinone ( 2c ), respectively. Although Tl(OCOF₃)₃ is less effective for the oxidation of 1a-c , it proves to be the reagent of choice for converting partially etherified or esterified calixarenes carrying p-tert-butyl groups directly to partially quinonoid calixarenes. Thus, monosubstituted calix[4]arenes yield triquinones; disubstituted calix[4]arenes yield diquinones; trisubstituted calix[4]arenes yield monquinones; and tetrasubstituted calix[6]arenes yield diquinones. The structures of the calixquinones have been established by elemental analysis, ¹H NMR spectroscopy, mass spectroscopy, and in the case of 2c by X-ray crystallography. Since the starting materials are readily accessible, the calixquinones become easily available compounds for further study.     

Effect of chain rigidity on block copolymer micelle formation and dissolution as observed by 1H-NMR spectroscopy

Amphiphilic copolymers poly(methyl methacrylate-b-acrylic acid), poly(methyl methacrylate-b-methacrylic acid), poly(methyl acrylate-b-acrylic acid) and poly(methyl acrylate-b-methacrylic acid) were prepared by reversible addition fragmentation chain-transfer (RAFT) polymerization. The hydrophilic polyacid blocks were either synthesized directly or formed by the hydrolysis of poly(tert-butyl acrylate) or poly(tert-butyl methacrylate) blocks. The hydrophobic blocks consisted of either the more rigid, high glass transition temperature (T _g ) poly(methyl methacrylate) or more flexible, low T _g poly(methyl acrylate) material. The hydrophilic blocks were either poly(methacrylic acid) (rigid, high T _g ) or poly(acrylic acid) (flexible, low T _g ). The micellization behavior of the polymers was studied by proton nuclear magnetic resonance (¹H-NMR) spectroscopy in mixtures of 1,4-dioxane-d₈ and D₂O. All four polymers were soluble in neat dioxane. In solutions of higher water content, the polymers with the more rigid hydrophobic blocks formed into micelles as was evidenced by broadening of the resonances resulting from the protons in those blocks. At moderate water concentration (25–50%), dissolution of the micelles was observed upon heating the solution. No micellization was observed in polymers containing the less rigid poly(methyl acrylate) hydrophobic block regardless of the identity of the hydrophilic block. As further evidence of micellization formation and dissolution, the spin-lattice (T ₁) and spin-spin (T ₂) relaxation times of protons in the hydrophobic and hydrophilic blocks were measured. Significant differences in the relaxation times as functions of temperature and solvent concentration were observed between the hydrophilic and hydrophobic blocks of the micelle-forming polymers.     

Synthesis and characterization of polyimides based on isopropylidene-containing bis(ether anhydride)s

Two bis(ether anhydride)s, 4,4′-[1,4-phenylenebis(isopropylidene-1,4-phenyleneoxy)]-diphthalic anhydride (IV _a) and 4,4′-[isopropylidenebis(1,4-phenylene)dioxy]diphthalic anhydride (IV _b), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of 4-nitrophthalonitrile with α,α ′-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene (I _a) and 4,4′-isopropylidenediphenol (I _b) in N,N-dimethylformamide (DMF) in the presence of potassium carbonate. The bis(ether anhydride)s IV _a and IV _b were polymerized with various aromatic diamines to obtain two series of poly(ether amic acid)s VI _a–g and VII _a–g with inherent viscosities in the range of 0.30∼0.74 and 0.29∼1.01 dL/g, respectively. The poly(ether amic acid)s were converted to poly(ether imide)s VIII _a–g and IX _a–g by thermal cyclodehydration. Most of the poly(ether imide)s could afford flexible and tough films, and they showed high solubility in polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and m-cresol. The obtained poly(ether imide) films had tensile strengths of 45∼83 MPa, elongations-to-break of 6∼27%, and initial modulus of 0.6∼1.7 GPa. The T_gs of poly(ether imide)s VIII _a–g and IX _a–g were in the range of 194∼210 and 204∼243 °C, respectively. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500 °C in both air and nitrogen atomspheres.     

Preparation and dynamic mechanical properties of poly(styrene‐b‐butadiene)‐modified clay nanocomposites

Polybutyl acrylate (PBA) was intercalated into clay by the method of multistep exchange reactions and diffusion polymerization. The clay interlayer surface is modified, and obtaining the modified clay. The structures of the clay‐PBA, clay‐GA (glutamic acid), and the clay‐DMSO (dimethyl sulfoxide) were characterized using X‐ray diffraction (XRD). The new hybrid nanocomposite thermoplastic elastomers were prepared by the clay‐PBA with poly(styrene‐b‐butadiene) block copolymer (SBS) through direct melt intercalation. The dynamic mechanical analysis (DMA) curves of the SBS/modified clay nanocomposites show that partial polystyrene segments of the SBS have intercalated into the modified clay interlayer and exhibited a new glass transition at about 157°C (T_g3). The glass transition temperature of polybutadiene segments (T_g1) and polystyrene segments out of the modified clay interlayer (T_g2) are about ?76 and 94°C, respectively, comparied with about ?79 and 100°C of the neat SBS, and they are basically unchanged. The T_g2 intensity of the SBS‐modified clay decreases with increasing the amounts of the modified clay, and the T_g3 intensity of the SBS‐modified clay decreases with increasing the amounts of the modified clay up to about 8.0 wt %. When the contents of the modified clay are less than about 8.0 wt %, the SBS‐modified clay nanocomposites are homogeneous and transparent. The T_gb and T_gs of the SBS‐clay (mass ratio = 98.0/2.0) are ?78.39 and 98.29°C, respectively. This result shows that the unmodified clay does not essentially affect the T_gb and T_gs of the SBS, and no interactions occur between the SBS and the unmodified clay. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1499–1503, 2002; DOI 10.1002/app.10353     

Core–shell particles to toughen epoxy resins. I. Preparation and characterization of core–shell particles

A two-stage, multistep soapless emulsion polymerization was employed to prepare various sizes of reactive core–shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA) copolymerizing with various concentrations of glycidyl methacrylate (GMA) as the shell. Ethylene glycol dimethacrylate (EGDMA) was used to crosslink either the core or shell. The number of epoxy groups in a particle of the prepared CSP measured by chemical titration was close to the calculated value based on the assumption that the added GMA participated in the entire polymerization unless it was higher than 29 mol %. Similar results were also found for their solid-state ^13C-NMR spectroscopy. The MMA/GMA copolymerized and EGDMA-crosslinked shell of the CSP had a maximum glass transition temperature (T_g) of 140°C, which was decreased with the content of GMA at a rate of −1°C/mol %. However, the shell without crosslinking had a maximum T_g of 127°C, which decreased at a rate of −0.83°C/mol %. The T_g of the interphasial region between the core and shell was 65°C, which was invariant with the design variables. The T_g of the BA core was −43°C, but it could be increased to −35°C by crosslinking with EGDMA. The T_g values of the core and shell were also invariant with the size of the CSP. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2069–2078, 1998     

Syndiotactic polymerization of methyl methacrylate with Ni(acac)<Subscript>2</Subscript>-methylaluminoxane catalyst

In this study, syndiotactic-rich poly(methyl methacrylate) (PMMA) is obtained by using a soluble nickle acetylacetonate [Ni(acac)₂] and modified methylaluminoxane (MMAO-3A) catalyst system under modest polymerization conditions. The main purpose of this work is concerned with the study of previous conflicting stereospecificity data. Types of MAO, temperature of polymerization, MAO/Ni(acac)₂ (Al/Ni) mole ratio, and various solvents have been investigated in the MMA polymerization. Particularly, high syndiotactic PMMA [(rr) > 91 %] has been obtained when MMAO-3A is used as cocatalyst with Al/Ni ratio of ca. 50 or polymerization temperature ca. 0 °C. As expected, the prepared syndiotacticity-rich PMMA has a higher glass transition temperature (T _g) within 120 ~ 127 °C. The details of the polymerization mechanism, especially in relation to the stereoregularity problems are under investigation.     

Synthesis and properties of aromatic polyimides based on ether-sulfone-diamines

Two diamine monomers, 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline (III _a ) and 4,4′-[sulfonylbis(2,6-dimethyl-l,4-phenyleneoxy)]dianiline (III _b ), were prepared by an aromatic nucleophilic substitution of 4,4′-sulfonyldiphenol (I _a ) and 4,4′-sulfonylbis(2,6-dimethylphenol) (I _b ) with p-chloronitrobenzene in the presence of potassium carbonate, followed by hydrazine catalytic reduction of the intermediate dinitro compounds. The diamines III _a and III _b were used as monomers with various aromatic tetracarboxylic dianhydrides (IV _a–f ) to synthesize polyimides. The polymerization was conducted in two steps via the formation of a poly(amic acid) precursor followed by thermal cyclodehydration. The poly(amic acid)s had inherent viscosities above 0.87 and up to 2.56 dL/g. Most poly(amic acid)s could be coated and thermodehydrated into flexible and transparent polyimide films. The polyimides derived from the dianhydrides containing-O-and-SO₂-or-C(CF₃)₂-bridging groups between the phthalic anhydride units were soluble in some organic solvents such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF). The glass transition temperatures (T_g) of the polyimides were in the range from 254 to 300 °C. The methyl-substituted polyimides exhibited slightly higher solubility and higher T_g compared to the corresponding unsubstituted polyimides. Thermogravimetric analysis (TG) showed that the polyimides containing methyl substitutents started to lose weight around 450 °C and the unsubstituted ones started to lose weight around 550 °C.     

Mid-IR real-time monitoring of the carbocationic polymerization of isobutylene and styrene

The in-situ monitoring of the living carbocationic polymerization of isobutylene (IB) and styrene (St) with a fiber optic Attenuated Total Reflection (ATR) probe in the mid-IR "fingerprint" range is reported here for the first time. Monomer consumption was followed by the disappearance of the C=C stretching for both IB and St, and the C−H bending of the CH₃-group in IB. The formation of polyisobutylene (PIB) was also monitored by tracing the asymmetrical doublet characteristic of C−H bending of the t-butyl groups of the PIB. Conversion measurements by conventional off-line gravimetry correlated well with the new technique. Received: 27 August 1997/Revised version: 2 November 1997/Accepted: 20 November 1997