Organic hybrid of chlorinated polyethylene and hindered phenol. III. Influence of the molecular weight and chlorine content of the polymer on the viscoelastic properties

The influences of the molecular weight and chlorine content of chlorinated polyethylene (CPE) on the dynamic mechanical propertiesof an organic hybrid consisting of CPE and 3,9‐bis[1,1‐dimethyl‐2{β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionyloxy}ethyl]‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) were investigated. All CPE/AO‐80 hybrids clearly exhibited two kinds of relaxations, and their magnitudes varied according to the molecular weight and chlorine content of CPE. This was due to a change in the ratio of AO‐80 molecules dispersed in the CPE‐rich domain and the AO‐80‐rich domain. A comparison of the jump intensity in differential scanning calorimetry curves with the maximum value of the second tan δ peak demonstrated that the second relaxation was caused by the dissociation of intermolecular hydrogen bonding within the AO‐80‐rich domain. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2943–2953, 2000     

Organic hybrid of chlorinated polyethylene and hindered phenol. IV. Modification on dynamic mechanical properties by chlorinated paraffin

Binary systems of chlorinated polyethylene (CPE) and chlorinated paraffin (CP) or 3,9‐bis[1,1‐dimethyl‐2{β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl) propionyloxy}ethyl]‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) and their ternary systems were investigated by dynamic mechanical analysis, thermal analysis, and infrared spectrum analysis. Adding CP into CPE/AO‐80, in which one novel relaxation appears above the glass‐transition temperature of CPE, can increase not only the peak height but also the minimum value between two peaks. The tan δ value in the middle of the two peaks for CPE/CP/CPE was found to be proportional to the slope (d ln E′/dT) of the E′ curve at an identical temperature. The addition of CP caused changes in many of the hydrogen bonds: a decrease in hydrogen bonds between the hydroxyl groups of AO‐80, a reinforcement of hydrogen bonds between the hydroxyl groups of AO‐80 and α‐hydrogens of CPE, and the formation of other hydrogen bonds between the carbonyl groups of AO‐80 and α‐hydrogens of CPE. Those changes are useful to improve the temperature dependence of tan δ and to enhance the stability of the dynamic mechanical properties. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 23–31, 2001     

Crystallization of a vitrified hindered phenol within chlorinated polyethylene and its effects on dynamic mechanical properties

The effects of heat treatment below the melting point of 3,9‐bis{1,1‐dimethyl‐2[β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl)propionyloxy]ethyl}‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) on the thermal and dynamic mechanical properties and microstructure of chlorinated polyethylene (CPE) filled with vitrified AO‐80 particles were investigated. The initial AO‐80 was a complete crystal, whereas AO‐80 obtained by cooling from its melting state was amorphous. The vitrified AO‐80 particles could crystallize again in a CPE matrix by an annealing treatment, but this crystal was different from the initial AO‐80 in the microstructure. In addition, the incorporation of CPE chains caused a dramatic increase in the modulus. As a result, the AO‐80 crystal particles that contained some CPE chains acted as multifunctional crosslinks, and the CPE/AO‐80 hybrid was found to be a new type of elastomer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 209–215, 2004     

Organic hybrid of chlorinated polyethylene and hindered phenol. I. Dynamic mechanical properties

Dynamic mechanical properties and microstructure of an organic hybrid consisting of chlorinated polyethylene (CPE) and 3,9‐bis[1,1‐dimethyl‐2{β‐(3‐tert‐butyl4‐hydroxy‐5‐methylphenyl)propionyloxy}ethyl]‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) were investigated. The AO‐80 clearly exhibited two second‐order transitions at 6 and 69 °C in addition to the melting: the transition at lower temperature is assigned to the glass transition, and the transition at higher temperature is considered to be caused by the dissociation of hydrogen bond between the hydroxyl groups of AO‐80. When blending with CPE, part of AO‐80 molecules was dispersed into the CPE matrix, and most of them formed an AO‐80‐rich phase. As a result, a novel transition appeared above the glass‐transition temperature of the CPE matrix. It was assigned to the dissociation of the intermolecular hydrogen bond between the α‐hydrogen of CPE and the hydroxyl groups of AO‐80 within the AO‐80‐rich phase. Dynamic mechanical properties and microstructure of CPE/AO‐80 hybrid were controlled by the thermal treatment. It was found that the CPE/AO‐80 hybrid is a good damping material and shows a shape memory effect. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2285–2295, 2000     

Highly stable rigid main‐chain nonlinear optical polymers with nematic phase: Effect of liquid‐crystalline phase on nonlinear optical response

Nonlinear optical (NLO) rigid main‐chain polyesters containing azobenzene mesogens with high thermal and temporal stabilities were synthesized from derivatives of hydroxyphenylazobenzoic acid. The NLO properties of the homopolymer, poly[4‐(4‐hydroxy‐3‐methyl phenyl)azo]benzoic acid, and copolymers of 4‐[(4‐hydroxy‐3‐methylphenyl)azo]benzoic acid, 4‐[(4‐hydroxy‐2‐methylphenyl)azo]benzoic acid, and 4‐[(4‐hydroxy‐2‐pentadecyl phenyl)azo]benzoic acid (PSCpHBA) with p‐HBA were measured by the Maker fringe technique. The thermal and liquid‐crystalline (LC) phase behaviors of the polymers were examined by differential scanning calorimetry, a thermal‐stimulated polarization current, and polarized light microscopy. The polymers except PSCpHBA exhibited nematic‐threaded and Schlieren textures. The LC orientations give rise to an enhanced NLO response. The polymers had high thermal and temporal stabilities for second‐harmonic generation activity because of their rigid aromatic backbone. This study suggests that the rigid aromatic main chain exhibiting an LC phase is a promising simple method to synthesize highly stable NLO polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1527–1535, 2003     

The Behavior of 2‐Substituted‐3‐hydroxyisoindolinones in the Reaction with sec‐Butyllithium

This paper presents a dualistic behavior of 2‐substituted‐3‐hydroxyisoindolones in reactions with sec‐butyllithium (sec‐BuLi). 2‐tert‐Butyl‐3‐hydroxy‐2,3‐dihydro‐1H‐isoindol‐1‐one ( 1a ) treated with sec‐BuLi undergoes metalation at position 7. On the other hand, the reaction between 3‐hydroxy‐2‐phenyl‐2,3‐dihydroxyisoindol‐1‐one ( 1j ) and sec‐BuLi results in 3‐sec‐butyl‐2‐phenyl‐2,3‐dihydroisiondol‐1‐one ( 3j ).     

Novel miktofunctional initiator for the preparation of an ABC‐type miktoarm star polymer via a combination of controlled polymerization techniques

An ABC‐type miktoarm star polymer was prepared with a core‐out method via a combination of ring‐opening polymerization (ROP), stable free‐radical polymerization (SFRP), and atom transfer radical polymerization (ATRP). First, ROP of ϵ‐caprolactone was carried out with a miktofunctional initiator, 2‐(2‐bromo‐2‐methyl‐propionyloxymethyl)‐3‐hydroxy‐2‐methyl‐propionic acid 2‐phenyl‐2‐(2,2,6,6‐tetramethyl‐piperidin‐1‐yl oxy)‐ethyl ester, at 110 °C. Second, previously obtained poly(ϵ‐caprolactone) (PCL) was used as a macroinitiator for SFRP of styrene at 125 °C. As a third step, this PCL–polystyrene (PSt) precursor with a bromine functionality in the core was used as a macroinitiator for ATRP of tert‐butyl acrylate in the presence of Cu(I)Br and pentamethyldiethylenetriamine at 100 °C. This produced an ABC‐type miktoarm star polymer [PCL–PSt–poly(tert‐butyl acrylate)] with a controlled molecular weight and a moderate polydispersity (weight‐average molecular weight/number‐average molecular weight < 1.37). The obtained polymers were characterized with gel permeation chromatography and ¹H NMR. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4228–4236, 2004     

Synthesis of tetracyclic system of 2,4‐di(tert‐butyl)‐6,7‐dihydrofuro[2′,3′:3,4]cyclohepta[1,2‐b]indole

For the first time, tetracyclic compounds, namely, furo[2′,3′:3,4]cyclohepta[1,2‐b]indoles were synthesized by recyclization of ortho‐substituted aryldifurylmethanes containing tert‐butyl groups at C5 positions of the furan rings. It was shown that [2‐(benzoylamino)phenyl]bis(5‐tert‐butyl‐2‐furyl)methanes 12 are transformed into tetracycles 15 at room temperature under treatment with POCl₃ in benzene solution containing some drops of water. The reaction proceeds via the intermediate formation of 1‐benzoylamino‐3‐(5‐tert‐butyl‐2‐furyl)‐2‐(4,4‐dimethyl‐3‐oxopentyl)indoles 14 which can be isolated from the reaction mixture. The method is very simple but its application is restricted due to side reactions if electron‐releasing groups are present in 12 . On the other hand, the decrease of electron density on furan ring in the starting compounds (for example, the use of [2‐X‐phenyl]difurylmethanes (where X = tosylamino or hydroxy group) prevents cyclization under the studied reaction conditions. As a result, corresponding ketones are formed as products of recyclization. J. Heterocyclic Chem., (2011).     

Optimization of the nitroxide‐mediated radical polymerization conditions for styrene and tert‐butyl acrylate in an automated parallel synthesizer

Automated parallel synthesizers provide fast and comparable screening of different polymerization parameters under similar conditions. In addition, these robotic systems eliminate handling errors, which may affect the results of a kinetic experiment more than the effect of an important parameter. The polymerization temperature and N,N‐tert‐butyl‐N‐[1′‐diethylphosphono‐2,2′‐dimethylpropyl]nitroxide concentration were optimized for the homopolymerization of both styrene and tert‐butyl acrylate to improve the control over the polymerization while reasonable polymerization rates were retained. Subsequently, polystyrene and poly(tert‐butyl acrylate) macro initiators were synthesized according to the knowledge obtained from the screening results. These macroinitiators were used for the preparation of block copolymers consisting of styrene and tert‐butyl acrylate. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6202–6213, 2006     

Viscoelastic properties of an organic hybrid of chlorinated polyethylene and a small molecule

The dynamic mechanical properties of an organic hybrid consisting of chlorinated polyethylene (CPE) and N,N‐dicyclohexyl‐2‐benzothiazolyl sulfenamide (DZ) were investigated. All the CPE/DZ hybrids showed a single loss tangent (tan δ) peak in the mechanical spectra. The peak area under the tan δ/temperature curves around the mechanical loss peak was examined to characterize the damping properties of the CPE/DZ hybrids. We found that there exists a bending point in the relation between the glass‐transition temperature (T_g) and DZ content and that the value of T_g is saturated in the higher DZ contents, suggesting that excess DZ molecules show self‐aggregation and are reorganized. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1341–1347, 2000     

Molecular relaxations in ester‐terminated,amide‐based dendrimers

This study utilized Matrix Assisted Laser Desorption/Ionization Time‐of‐Flight Mass Spectrometry, Thermogravimetric Analysis, Differential Scanning Calorimetry, X‐Ray Diffraction, and Dielectric Analysis to assess the viscoelastic and structural properties of three generations of tert‐butyl and methyl ester, amide‐based dendrimers. The effect of generation number and functionality on glass‐transition temperatures and corresponding apparent activation energies, obtained via adherence to WLF behavior, were determined. Both were found to increase with increasing generation number and bulkiness of terminal functionalities. WLF constants, C₁ and C₂, allowed the determination of free volume, and thermal expansion coefficients, respectively. Secondary transitions, conforming to Arrhenius behavior, were also characterized and increased in temperature with generation number. The apparent activation energy was greater when the matrix was crystalline. Dielectric relaxation responses were analyzed to yield dielectric strengths of the molecular relaxations which increased with generation number and were comparable for both tert‐butyl and methyl esters in the glass‐transition region. Electrical properties of the dendrimers were dominated by ionic conductivity in the high temperature region. In order to unmask the glass transition, the data were treated in terms of the electric modulus. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2025–2038, 1999     

New Aspects of 1,3‐Diphosphacyclobutane‐2,4‐diyls

1,3‐Di(tert‐butyl)‐2,4‐bis[2,4,6‐tri(tert‐butyl)phenyl]‐1,3‐diphosphacyclobutane‐2,4‐diyl was formed from [2,4,6‐tri(tert‐butyl)phenyl]phosphaacetylene and t‐BuLi. In addition, the X‐ray diffraction analysis was carried out, together with theoretical calculations of the structure and NMR data.     

Conformational Analysis and Selection of Odor‐Active Conformers: Synthesis of Molecules Designed for the Lily‐of‐the‐Valley(Muguet)‐Type Odor

The selection of odor‐active conformers and the construction of a model for a targeted odor type, i.e., for the lily‐of‐the‐valley odor, were examined. The disagreement of the odors of 1,3,4,5‐tetrahydro‐2‐benzoxepin derivative 1 and 3‐[4‐(tert‐butyl)phenyl]‐2‐methylpropanal ( 2 ) is discussed in terms of their stable conformers. The conformer active for the lily‐of‐the‐valley odor was investigated by conformational analyses of several related compounds. Based on the integrated model consisting of the assumed active conformers (Fig. 5), compounds anticipated to possess the lily‐of‐the‐valley odor were designed and synthesized. The odor of synthetic 7‐(tert‐butyl)‐1,2,4,5‐tetrahydro‐3H‐benzocyclohepten‐3‐one ( 8 ) and 3‐[4‐(tert‐butyl)phenyl]cyclopentanone ( 13 ) were evaluated by perfumers to have a floral odor and to recall the lily‐of‐the‐valley and lilac odors, respectively. Our methodology to design new odoriferous compounds, based on conformational analysis, selection of odor‐active conformers, and construction of a model, proved to be satisfactory.     

Ethylene polymerization by chromium complexes with phosphorous‐bridged bisphenoxy ligand

Chromium catalysts combined with phosphorous‐bridged bisphenoxy ligands were found to be highly active for ethylene polymerization. The most efficient catalyst precursor among them, generated by combining bis[3‐tert‐butyl‐5‐methyl‐2‐hydroxyphenyl](phenyl)phosphine hydrochloride ( 1a ) and CrCl₃(THF)₃, was characterized. X‐ray analysis of (3‐tert‐butyl‐5‐methyl‐2‐phenoxy)(3‐tert‐butyl‐5‐methyl‐ 2‐hydroxyphenyl)(phenyl)phosphine bis(tetrahydrofuran)chromium dichloride ( 6 ), obtained by the reaction of 1a and CrCl₃(THF)₃ in the presence of NaH, revealed a unique structure in which one phenol moiety of the bisphenol did not coordinate to the chromium center. Complex 6 showed higher activities than those observed in the in situ catalyst system. Polyethylene of various molecular weights was obtained with differing activators. The highest activity (113.5 kg mmol (cat)^?1 h^?1) was observed when TIBA/TB was used as a cocatalyst. A medium molecular weight polymer with narrow molecular weight distribution (M_w = 128,700, M_w/M_n = 1.8) was obtained using a 6 ‐TIBA/B(C₆F₅)₃ system. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3668–3676, 2007     

Inclusion of HNEt3+ in an acyclic tetraphenolate

The acyclic tetraphenolic derivative 2,2′‐methyl­ene­bis[6‐(3‐tert‐butyl‐2‐hydroxy‐5‐methyl­benzyl)‐4‐methyl­phenol] reacts with excess triethyl­amine in aceto­nitrile to form a molecular complex, i.e. triethyl­ammonium 2‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl)‐6‐[3‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl)‐2‐hydroxy‐5‐methylbenzyl]‐4‐methylphenolate aceto­nitrile sol­vate, C₆H₁₆N⁺·­C₃₉H₄₇O₄^?·­C₂H₃N, where the organic HNEt₃⁺ cation is included in the partial cone defined by the aromatic faces of the acyclic poly­phenolate.     

Attempt to Synthesize Hindered 2,4,6‐Tri‐Aryloxy‐s‐Triazines: Bis(2,4‐di‐tert‐Butylphenyl) Carbonate – Crystal Structure

Some less hindered 2,4,6‐tri‐aryloxy‐s‐triazines were synthesized through the reaction of the corresponding phenols as a starting materials with cyanogen bromide (BrCN) to obtain the corresponding arylcyanates and then trimerized. Unexpectedly, 2,4‐di‐tert‐butyl‐1‐cyanatobenzene derived from 2,4‐di‐tert‐butylphenol did not trimerize but, indeed, yielded bis(2,4‐di‐tert‐butylphenyl) carbonate. The structures of 2,4,6‐tri‐aryloxy‐s‐triazines and bis(2,4‐di‐tert‐butylphenyl) carbonate were characterized by means of IR, ¹H, and ¹³C NMR spectroscopies. Also the structure of the latter compound was studied by X‐ray crystallography.     

Hydrophilic graft modification of a commercial crystalline polyolefin

Hydroxy‐functionalized isotactic poly(1‐butene) was synthesized using transition metal‐catalyzed regioselective C? H borylation at the side chain of the commercial polyolefin and subsequent oxidation of the boronic ester functionality. Functionalization up to ～ 19 mol % of the termini of the ethyl side chain occurred without significant side reactions that could alter the polymer chain length. Esterification of the hydroxy group in the polymer with 2‐bromoisobutyl bromide generated a side chain‐functionalized polyolefin macroinitiator. Atom transfer radical polymerization of tert‐butyl acrylate from the macroinitiator produced a high molecular‐weight graft copolymer of the polyolefin, isotactic poly(1‐butene)‐graft‐poly(tert‐butyl acrylate) (PB‐g‐PtBA). Finally, the hydrolysis of the tert‐butoxy ester group of PB‐g‐PtBA created an amphiphilic polyolefin, isotactic poly(1‐butene)‐graft‐poly(acrylic acid), which contained a short carboxylic acid‐functionalized polymer block at the side chain. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3533–3545, 2008     

Initiation of free‐radical polymerization by peroxypivalates studied by electrospray ionization mass spectrometry

Initiation by tert‐butyl peroxypivalate (TBPP), tert‐amyl peroxypivalate (TAPP), 1,1,3,3‐tetramethylbutyl peroxypivalate (TMBPP), or 1,1,2,2‐tetramethylpropyl peroxypivalate (TMPPP) of radical polymerization of methyl methacrylate in toluene solution at 90 °C was studied via polymer end‐group analysis using electrospray ionization mass spectrometry (ESI‐MS). Conclusive peak assignments allowed for measuring the type and concentration of the fragments that actually initiate macromolecular growth after thermal decomposition of these peroxypivalates. It was found that the pivaloyloxy radical moiety undergoes instantaneous decarboxylation to yield an initiating tert‐butyl radical. The alkoxy radical moiety, on the other hand, may generate, via β‐scission reaction, different types of carbon‐centered radicals (together with a ketone) or may undergo a 1,5‐H‐shift reaction, by which reaction an oxygen‐centered radical is transformed into a carbon‐centered hydroxy radical. This hydrogen shift reaction was found in case of TMBPP. Surprisingly, no evidence for initiating alkoxy radicals could be found, not even in case of initiation by TBPP, where the intermediate tert‐butoxy radical undergoes a rapid chain‐transfer reaction with the solvent toluene. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4266–4275, 2004     

Synthesis of polar block grafted syndiotactic polystyrenes via a combination of iridium‐catalyzed activation of aromatic C?H bonds and atom transfer radical polymerization

A combination of iridium‐catalyzed C H activation/borylation and atom transfer radical polymerization (ATRP) was used to generate polar graft copolymers of syndiotactic polystyrene (sPS). The borylation at aromatic C H bonds of sPS and subsequent oxidation of boronate ester proceeded without negatively affecting the molecular weight properties and the tacticity of sPS. A macroinitiator suitable for ATRP could be synthesized by the esterification of 2‐bromo‐2‐methylpropionyl bromide and hydroxy‐functionalized sPS. The graft polymerizations of methyl methacrylate and tert‐butyl acrylate from the macroinitiator using ATRP afforded polar block grafted sPS materials, syndiotactic polystyrene‐graft‐poly(methyl methacrylate) (sPS‐g‐PMMA) and syndiotactic polystyrene‐graft‐poly(tert‐butyl acrylate) (sPS‐g‐PtBA). The latter was hydrolyzed to yield an amphiphilic graft copolymer, syndiotactic polystyrene‐graft‐poly(acrylic acid) (sPS‐g‐PAA). The structures of the copolymers were characterized by NMR and FTIR spectroscopies. Size exclusion chromatography and ¹H NMR spectroscopy were used to study any changes in the molecular weight properties from the parent polymer. A decrease in the hydrophobicity of the graft copolymers was confirmed by water contact angle measurements. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6655–6667, 2009     

Synthesis of soluble poly(para‐phenylene) with a long polymer chain: Characteristics of regioregular poly(1,4‐phenylene)

Soluble poly(para‐phenylene) having a long polymer chain (more than six repeat units) was synthesized with a tert‐butyl end‐group (t‐PPP) and was found to have improved solubility and excellent optical properties. Poly(1,3‐cyclohexadiene) (PCHD) consisting of only 1,4‐cyclohexadiene (1,4‐CHD) units was synthesized with a tert‐butyl end‐group (t‐PCHD), and completely dehydrogenated to obtain t‐PPP. This end‐group effectively prevented the crystallization of t‐PPP, and polymers containing up to 16 repeat units were soluble in tetrahydrofuran. Soluble t‐PPP obtained had an ability to form a tough thin film prepared by spin‐coating method. Optical analyses of t‐PPP provided strong evidence for a linear polymer chain structure. A block copolymer of t‐PPP and a soluble polyphenylene (PPH) was then synthesized, and the excellent optical properties were retained by this block copolymer along with its solubility. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5223–5231, 2008