Glass Transition Temperature Of Poly Research Articles

Radical polymerization of methacryloyl isocyanate containing 1-adamantanol

Radical polymerization of the methacryloyl isocyanate containing 1-adamantanol (Ad-MAI) with AIBN in different solvents at 60°C was investigated. It is observed that polymerization is slower in polar solvents than in nonpolar ones. The rate of polymerization for Ad-MAI was found to be slower than those of Adph-MAI and MMA both in photopolymerization and in thermal polymerization. Copolymerization of Ad-MAI (M1) with styrene (M2) in benzene was studied at 60°C. The monomer reactivity ratio was calculated to be r1=1.53 and r2=0.76 according to the method of Fineman-Ross. The prominent glass transition temperature for poly(Ad-MAI) was observed at 142°C from global TSC spectrum.

Molecular design of the polymer forming the complex with metal. [II]: poly (dimethyl siloxane) with pyridine ring

Poly(dimethyl siloxane)s (MPYSI) modified by the various types of N-pyrid-2-ylmethyl amide (MPY) group were synthesized. The thermal and mechanical properties of the MPYSIs and their complexes with ZnCl 2 were investigated. The MPYSI forms the stoichiometric 1:1 complex with ZnCl 2 to MPY group of MPYSI. Although the MPYSI is liquid, the complex is solid at room temperature and moreover the melting temperature of the complex is observed at 141°C. The complex also shows the rubbery plateau above the glass-transition temperature of poly(dimethyl siloxane) (−115°C). As the results, the complex exhibits thermoplastic and elastic properties which come from the unique complex structure.

Solid-state complexes of poly(L-histidine) with metal chlorides from the first row of thed-block

Solid-state characterization of poly(L-histidine) was obtained via differential scanning calorimetry, thermogravimetric analysis, optical microscopy, and infrared spectroscopy. The glass transition temperature of poly(L-histidine) is 169°C. This thermal transition has not been reported previously. Poly(L-histidine)'s Tg increases when complexes are produced with the following divalent transition metal chlorides: cobalt chloride hexahydrate, nickel chloride hexahydrate, copper chloride dihydrate, and anhydrous zinc chloride. At 10 mol % salt, nickel chloride increases Tg by 69°C. The enhancement in poly(L-histidine)'s Tg correlates well with ligand field stabilization energies for pseudo-octahedral dn complexes (n = 7, 8, and 10) from the first row of the d-block. However, d9 copper(II) complexes do not conform to this empirical correlation. Infrared spectroscopic evidence indicates that these metal chlorides form complexes with the imidazole ring in the histidine side group and the amide group in the main chain of the polymer. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 301–309, 1999

Hydrocarbon polymers containing six-membered rings in the main chain. Microstructure and properties of poly(1,3-cyclohexadiene)

The relationship between the microstructure and the properties of poly(1,3-cyclohexadiene)s, obtained by living anionic polymerization with an alkyllithium/ amine system, and their hydrogenated derivatives are reported. The 1,2-bond/1,4-bond molar ratio of poly(1,3-cyclohexadiene) was determined by measuring 2D-NMR with the H-H COSY method. The glass transition temperature of poly(1,3-cyclohexadiene) was found to rise with an increase in the ratio of 1,2-bonds to 1,4-bonds or with an increase of the number average molecular weight. The 1,2-bond of the polymer chain gives a high flexural strength and heat distortion temperature. Hydrogenated poly(1,3-cyclohexadiene) has the highest T g (231°C) among all hydrocarbon polymers ever reported. 1,3-Cyclohexadiene-butadiene-1,3-cyclohexadiene triblock copolymer and 1,3-cyclohexadiene-styrene-1,3-cyclohexadiene triblock copolymer have high heat resistance and high mechanical strength.

Influence of composition and glass transition temperature on the diffusion and solubility behaviour of methyl ethyl ketone-isopropyl alcohol mixtures in poly(methyl methacrylate)

R. A. Pethrick and K. E. Rankin, J. Mater. Chem., 1998, 8, 2591 DOI: 10.1039/A802466I

Synthesis of poly(silyl ether) by the addition reaction of bisphenol-S diglycidyl ether and dichlorodiphenylsilane

In this study, a new poly(silyl ether) with reactive pendant chloromethyl groups was synthesized by an addition reaction between dichlorodiphenylsilane (CPS) and the diglycidyl ether of bisphenol-S (bisphenol-S epoxy). The polyaddition proceeded very smoothly and regioselectively in toluene catalysed by quaternary ammonium or phosphonium salts such as tetrabutylammonium bromide, tetrabutylammonium fluoride and tetrabutylphosphonium bromide to produce a polymer with high molecular weight. The polyaddition also proceeded using triphenylphosphine as a catalyst to afford the poly(silyl ether), but with low molecular weight. On the other hand, the reaction did not occur without a catalyst under the same reaction conditions. Also, the nature of the catalyst and the reaction solvent influenced the polymer's yields and molecular weights. The glass transition temperature of poly(silyl ether) was 68°C and the X-ray diffraction pattern revealed that the polymer was semi-crystalline. Furthermore, experimental results indicated that the subsequent poly(silyl ether) based on bisphenol-S with reactive pendant chloromethyl groups exhibited excellent solubility in common organic solvents.

On the relationship between tacticity dependent molecular microstructure and glass transition temperature of poly(vinyl chloride): a novel approach through model polymers with controlled, chemically induced microstructure

Nucleophilic substitution in poly(vinyl chloride) (PVC) with sodium thiobenzoate (NaTBZ) has been studied in two kinds of solvent. From the evolution of the content of isotactic ( mr) and heterotactic ( mr) triads in the unmodified parts of the polymer, as investigated by 13C n.m.r., the reaction was found to behave similarly to that previously studied with sodium benzenethiolate (NaBT) in that only the local configurations mmr and rrmr at the end of isotactic and syndiotactic sequences respectively are reactive. The same reaction with both nucleophiles has also been studied in aqueous suspension in the presence of a phase transfer catalyst. In all cases the ratio of mmr content to rrmr content is found to vary according to the experimental conditions, in particular the type of solvent, irrespective of the nucleophile. Accordingly, model polymers having well known tacticity-derived microstructure can be obtained. On the other hand, the evolution of T g with degree of conversion has been studied by calorimetric measurements. T g has been found to change linearly with conversion and the correlation between the corresponding rates and the evolution of the ratio between the mmr and rrmr contents proves to be linear too. From these studies it follows that T g depends on two well defined factors: one, variable in character, is the nucleophile nature; the other is the microstructure in terms of the isotactic and syndiotactic sequences and, especially, the local configurations and conformations at the end of them. Interestingly, this effect is permanent in character and is independent of the substituent. The results that we have obtained provide new concepts on the involvement of some specific molecular microstructural features in the T g phenomenon.

The modification of lactic acid based poly(ester-urethane) by copolymerization

Copolymers of L-lactic acid (LLA) with DL-mandelic acid (DLMA), 4-hydroxybenzoic acid, 4-acetoxybenzoic acid, DL-malic acid, or anhydrous citric acid were synthesized via direct copolycondensation in the presence of 1,4-butanediol, using stannous octoate as catalyst. The effect of the comonomer and the comonomer ratio on polycondensation and the glass transition temperature were investigated. The glass transition temperature of amorphous poly(L-lactic acid-co-DL-mandelic acid) increased linearly from 33° to 56°C as the mandelic acid composition was increased from 0 to 45 mol %. For urethane synthesis, prepolymers of LLA and DLMA were condensation polymerized with compositions of 100/0, 90/10, and 80/20 (mol % in feed). The preparation of poly(ester-urethane) (PEU) was carried out in a stirred glass reactor, using 1,6-hexamethylene diisocyanate and isophorone diisocyanate in melt. The glass transition temperature of poly(L-lactic acid-co-DL-mandelic acid-urethanes) showed a marked increase with increased mandelic acid composition. The molecular weights of these urethanes were lower than for PEU based on poly(L-lactic acid). Such a depression in the degree of polymerization is attributed to the steric hindrance of the bulky phenyl group as a side chain of mandelic acid. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1865–1872, 1997

Preparation of core-shell polymer colloid particles by encapsulation

By means of heterocoagu-lation anionic poly-[styrene] particles were coated with smaller electro-sterically stabilised cationic particles of poly-[butyl methacrylate]. On heating the heterocoagulated units 45 °C above the glass transition temperature of poly-[butyl methacrylate], as predicted theoretically, the latter polymer spread over the surface of the poly-[styrene] particle to give a composite particle with a core-shell structure. It was found that the extent of packing of the small particles on the larger core particle was a critical feature of the coating process.

Syntheses and radical polymerizations of novel optically active vinyl and isopropenyl carbamates havingL-leucine structures

Syntheses and radical polymerizations of vinyl and isopropenyl carbamates having L-leucine methyl ester structures, N-vinyloxycarbonyl-L-leucine methyl ester (VOC-L-M) and N-isopropenyloxycarbonyl-L-leucine methyl ester (IOC-L-M), were carried out. VOC-L-M and IOC-L-M were prepared by the reactions of L-leucine methyl ester with vinyl and isopropenyl chloroformates in the presence of sodium hydrogen carbonate. The radical polymerization of VOC-L-M with AIBN (1 mol %) in bulk, chlorobenzene, methanol, and N,N-dimethylformamide afforded the corresponding polymer (poly(VOC-L-M)) with M n 7,400-19,000. Meanwhile, IOC-L-M afforded no polymer with AIBN at 60°C but afforded a polymer having low molecular weight with BPO at 80° C. The glass transition temperatures of poly(VOC-L-M) and poly(IOC-L-M) were 53 and 65°C, respectively. The 10% weight loss temperatures of poly(VOC-L-M) and poly(IOC-L-M) under nitrogen were 255 and 173, respectively. The copolymerization parameters of VOC-L-M (M 1 ) and vinyl acetate (M 2 ) were evaluated as r 1 = 0.92 and r 2 = 0.63.

Synthesis and biocidal activities of polymer. IV. Antibacterial activity and hydrolysis of polymers containing diphenyl ether

The antibacterial monomer, 2,4,4′-trichloro-2′-acryloyloxydiphenyl ether (AcDP) was synthesized from 2,4,4′-trichloro-2′-hydroxydiphenyl ether (DP) and acryloyl chloride in the presence of dry THF at 20°C. Copolymers of AcDP with acrylic acid [poly(AcDP-co-AA)] or 2-hydroxyethyl methacrylate [poly(AcDP-co-HEMA)] were synthesized using BPO as a thermal initiator at 70°C. The synthesized poly(AcDP-co-AA) and poly(AcDP-co-HEMA) were identified by IR and 1H-NMR spectra. The monomer reactivity ratios, r1 (AcDP) and r2 (AA), determined by the Kelen–Tudos method, were 0.21 and 1.28, respectively. The number average molecular weights of poly(AcDP-co-AA) and poly(AcDP-co-HEMA) were 2400 and 3000, respectively. The glass transition temperatures of poly(AcDP-co-AA) and poly(AcDP-co-HEMA) were 87 and 50°C, respectively. The rate of hydrolysis decreased in the order of poly(AcDP-co-AA) > AcDP > poly(AcDP-co-HEMA) > poly(AcDP). The antibacterial activities of poly(AcDP-co-AA) and poly(AcDP-co-HEMA) were studied against Staphylococcus aureus by the shake flask test. The antibacterial activity of poly(AcDP-co-AA) was higher than that of poly(AcDP-co-HEMA). The trend of magnitude of the antibacterial activities for copolymers containing the AcDP unit was in agreement with that of the rate of hydrolysis for the copolymers. © 1996 John Wiley & Sons, Inc.

Synthesis and characterization of biodegradable poly(1,4‐butanediol succinate)

AbstractBiodegradable poly(1,4‐butanediol succinate) was synthesized from 1,4‐butanediol and succinic anhydride. The synthesized polymer was identified by 1H‐NMR spectrometer and FT‐IR spectrophotometer. The weight average molecular weights were between 4,600 and 29,000, and molecular weight distributions were in the range of 1.7 and 1.9. The glass transition temperature of poly(1,4‐butanediol succinate) was revealed at 73°C. The crystallization and cold crystallization of the polymers were investigated as a function of heating rate, cooling rate, reheating rate, and molecular weight. The biodegradation behavior of poly(1,4‐butanediol succinate) in micro‐organisms such as fungi, actinomycetes, and bacteria was studied by using modified ASTM method. Based upon visual observation, the crystalline structure of films composed of larger molecular weight polymers retained their crystallinity longer than similar structures in low molecular weight samples. © 1995 John Wiley & Sons, Inc.

Polymer—polymer complexation between poly(monomethyl itaconate) and poly(vinylpyridine)s

Polymer-polymer hydrogen-bonded complexes of poly(monomethyl itaconate) with poly(2-vinylpyridine) and poly(4-vinylpyridine) were studied. Several solvents have been assayed for these systems: methanol, methylformamide and binary mixtures ( 50 50 ) of methanol with water, tetrahydrofuran, dimethylformamide and dimethylacetamide. In all cases, instantaneous precipitate formation was observed after mixing the solutions of poly(monomethyl itaconate) and poly(vinylpyridine)s. Polymer complexes prepared from methanol solutions show different stoichiometries depending on the feed composition, but that found in most cases was 3 : 2 of monomethyl itaconate:vinylpyridine repeat units. Complexes are insoluble in all the tested solvents; only fresh precipitate may be solubilized by increasing the pH of the solution. Complex formation is observed even when the density of pyridine groups is reduced to 25% by copolymerization with styrene. Differential scanning calorimetry analyses do not show a glass transition temperature for poly(monomethyl itaconate) polymer complexes; only a wide degradation peak was observed. Thermogravimetric experiments corroborate that the thermal degradation behaviour does not differ substantially from that of the pure components. In these conditions, Fourier-transform infra-red spectroscopy was used to study their hydrogen-bonding interactions. The infra-red spectra corresponding to polycomplexes clearly show evidence of hydrogen bonding between the components and there seems to be some evidence of partial pyridine protonation.

Chemical modification of poly(styrene‐co‐maleic anhydride) with primary N‐alkylamines by reactive extrusion

AbstractReactive melt‐processing of poly(styrene‐co‐maleic anhydride) (SMA) with primary N‐alkylamines was carried out in one step in a twin‐screw extruder. Ring formation of the imide occurred within the residence time of the extruder, at temperatures exceeding 220°C and with an excess of primary amines. The increasing chain length of grafted amine onto the SMA backbone depressed the glass transition temperature of poly(styrene‐co‐N‐alkylmaleimides) remarkably. © 1994 John Wiley & Sons, Inc.

On the glass transition temperature of styrene‐n‐butyl methacrylate copolymers in dependence on chemical composition, molecular weight, and mixtures

AbstractFor statistic copolymers of styrene and n‐butyl methacrylate, the relation between the glass transition temperature and the chemical composition or molecular weight of the copolymers has been determined. Further, the dependence of the glass transition temperature on the composition of binary and ternary blends from statistical poly (styrene‐co‐n‐butyl methacrylates) of a nearly equal chemical composition but a very different molecular weight has been studied. Among several equations considered for the correlation between glass transition temperature and composition of the mentioned copolymers with relatively low molecular weights, the Gordon/Taylor and Couchman equations gave the best agreement with the experimental results. For the glass transition temperature of poly(styrene‐co‐n‐butyl methacrylate) with an n‐butyl methacrylate content of about 30 wt % in dependence on the molecular weight, the Kanig‐Ueberreiter and Fox‐Flory equations proved to be useful for the examined molecular weight range. The glass transition temperatures of the polymer blends have been studied for a low/high‐molecular component system, a system of two low‐molecular components, as well as for systems with a third component. The glass transition temperatures of the mixtures frequently exceeded those of their individual components. © 1994 John Wiley & Sons, Inc.

Radical polymerization of alkyl crotonates as 1,2‐disubstituted ethylenes leading to thermally stable substituted polymethylene

AbstractRadical polymerization of several alkyl crotonates (RCr) was carried out in bulk or in benzene in the presence of radical initiators. Homopolymerization of RCr bearing bulky ester alkyl groups, e.g. tert‐butyl (tBCr), 1‐adamantyl (AdCr), and 3,5‐dimethyl‐1‐adamantyl crotonate (DMAdCr) proceeded to give a polymer with molecular weight of several thousands despite of the steric hindrance and chain transfer by the presence of the β‐methyl group, while the methyl and ethyl esters gave no polymer. The kinetics of the polymerization was examined in detail and absolute rate constants were evaluated by means of electron spin resonance spectroscopy. The propagation rate constants of RCr were 0.41–1.0 L/mol s, being much smaller than those of the corresponding methacrylates (530–570 L/mol s). The termination rate constants were also determined from the analyses of steady state and non‐steady state polymerizations. Radical copolymerizations of AdCr (M2) with several vinyl monomers (M1) were carried out in bulk at 60°C and the rate constants for cross propagations were calculated to examine reactivities of the monomer and its polymer radical. The structure and thermal properties of the resulting poly (AdCr) were also investigated. Onset temperature of decomposition and glass transition temperature of poly(AdCr) were revealed to be much high as 302 and 234°C, respectively. © 1994 John Wiley & Sons, Inc.

Glass transition temperature for blends containing poly(4-hydroxystyrene)

The glass transition temperature of poly(4-hydroxystyrene) with poly(vinylacetate), poly(methylmethacrylate) and various poly(acrylates) have been obtained over the whole composition range. The effect of the size of the side-chain group upon the miscibility has been found to be important, leading to partial miscibility for the blends with poly(n-butylacrylate) and poly(methylmethacrylate). On the other hand, the solvent from which the blend is cast has a noticeable effect on the composition dependence of the glass transition temperatures. Finally, the composition dependence of the glass transition temperatures of miscible blends has been correlated in terms of some lattice models.

Segment Orientation in a Quiescent Block Copolymer Melt Studied by Raman Scattering

Segment orientation of a poly(styrene)-poly(butadiene) star diblock copolymer melt is investigated using polarization-modulated laser Raman scattering (PMLRS). The PMLRS technique is based on Raman spectroscopy and allows for the simultaneous measurement of statistical segment orientation and birefringence. It is found that at temperatures below the T g of poly(styrene), segments in both poly(styrene) and poly(butadiene) blocks preferentially normal to the interface separating microdomains. However, at temperatures greater than the glass transition temperature of poly(styrene), segment orientation disappears. At this temperature, a dramatic decrease in birefringence is also observed

Synthesis of poly {4-[bis(trimethylstannyl)methyl]styrene} and its properties for electron-beam resist

To create high performance resist materials, synthesis of novel organostannun-containing polymer was investigated. 4-[Bis(trimethylstannyl)methyl]styrene (BSnMS) was synthesized by a reaction between trimethylstannyl chloride and 4-vinylbenzyllithium that was prepared through a metalation reaction of 4-methylstyrene by lithium diisopropylamide. Radical polymerization of BSnMS proceeded smoothly to give a polymer. Glass transition temperature of poly(BSnMS) (Tg=140°C) was fairly high among polystyrene homologues. Poly(BSnMS) thus obtained showed naga-working properties toward EB exposure. Sensitivity of the poly(BSnMS) was 9.0∼9.6 mC cm-2, keeping high γ-value (3.2∼4.9).

Effect of large polar side groups on the glass transition temperature of acrylic copolymers

The glass transition temperatures of poly[N-[4-(methacryloyloxy)phenyl]-2-(4-methoxyphenyl)-acetamide] (poly-O) and poly[N-[4-[[(4-methoxyphenyl)acetyl]oxy]phenyl]methacrylamide] (poly-A) are discussed on the basis of the structural characteristics of the corresponding monomeric units, taking into consideration that both 0 and A have the same substituents but functional groups with opposite orientation, in such a way that O is a methacrylic ester, whereas A is a methacrylamide. The variation of the T g s of copolymers with hydroxyethyl methacrylate is discussed on the basis of treatments which consider the influence of the distribution of monomeric units on the T g s of the copolymer samples, determining the T g s of the corresponding alternating diads, T gOH and T gAH