Mark Houwink Sakurada Equation Research Articles

Interchain ordering structure and main chain conformation analysis of thermal stability in vinyl-addition polynorbornene

The aggregation structure and formation mechanism during film casting using toluene of vinyl-addition poly(norbornene- co -hexylnorbornene)s (P(NB/HNB)s) synthesized using Ni and Pd catalyst were systematically investigated by wide- and small-angle X-ray scattering and gel permeation chromatography–right-angle laser light scattering–viscometry techniques. The correlation of these data with the glass-transition temperature ( T g ) was discussed. The single-chain conformation of P(NB/HNB)s was a flexible, stretched structure with respect to the Gaussian chain in a good solvent, as characterized by an exponent of the Mark–Houwink–Sakurada equation, and P(NB/HNB)s formed thin-rod aggregates with a length of 30 nm in semi-concentrated toluene solution via interchain stacking of the rod-like chains. P(NB/HNB) films cast from toluene solution exhibit interchain ordering structures with distances between 0.9 and 1.7 nm depending on the NB/HNB ratio. These findings show that the interchain ordering is driven by the stacking of the rod-like chains, which resulted in the highly ordered interchain structure in the film. The T g of the Pd-catalyzed polymer films were 20 °C higher than that of the Ni-catalyzed polymer films depending on the interchain structure. There is a strong correlation between interchain ordering structure and T g , which shows that the T g of P(NB/HNB)s is primarily influenced by the van der Waals interaction between main chains. • Aggregation structure and mechanism of vinyl-addition polynorbornenes was investigated. • The polymers formed thin-rod aggregates in semi-concentrated solution and highly ordered interchain structure in the film. • The interchain ordering was driven by the stacking of the rod-like chains during drying process. • There is a strong correlation between T g of the film and the interchain ordering structure.

Study of molar properties of GO after doping with transition metals for photodegradation of fluorescent dyes.

We synthesized graphene oxide (GO) doped with transition metal ions and characterized it using XPS, FT-IR, TGA/DTG, XRD, SEM, AFM, ICP-OES, UV/vis, and Raman spectroscopy. An intrinsic viscosity [η] of 0.002-0.012 g% @ 0.002 aq-GO was determined for viscosity average molecular weight (M v) of GO at 288.15, 298.15, and 308.15 K. Mark-Houwink (M-H) constants k (cm3 g-1) and a (cm3 mol g-2) were calculated for 5-15 mg/100 mL polyvinylpyrrolidone (PVP), using 29, 40, 55 kg mol-1 as markers for calculating M v by fitting the [η] to the Mark-Houwink-Sakurada equation (MHSE). We obtained 48 134.19 g mol-1 M v at 298.15 K, and the apparent molar (V ϕ m , cm3 mol-1), limiting molar volumes (V 0 GO)GO⃑0, enthalpy (ΔH m, J mol-1), entropy (ΔS m, J mol-1 K-1), viscosity (η m, mPa s mol-1), surface tension (γ m, mN m-1 mol-1), friccohesity (σ m, scm-1 mol-1), fractional volume (ϕ m, cm3 mol-1), isentropic compressibility (K sϕ,m, 10-4 cm s2 g-1 mol), infer GO molar consistency throughout the chemical processes. Molar properties (MPs) infer a GO monodispersion producing negative electrons (e-) and positive holes (h+) under sunlight. The transition metal ions (Fe2+, Mn2+, Ni2+, Cr3+, TMI) doped onto GO (TMI-GO), can photodegrade methylene blue (MB) in 60 min compared with 120 min using GO alone. The 4011 C atoms, 688 hexagonal sheets, 222 π-conjugations, and 4011 FE were calculated from the 48 134.19 g mol-1. The functional edges are the negative and positive holes generating centres of the GO 2D sheets.

Conformational Behavior, Topographical Features, and Antioxidant Activity of Partly De-Esterified Arabinoxylans.

This study aimed to investigate the effect of arabinoxylans (AX) partial de-esterification with feruloyl esterase on the polysaccharide conformational behavior, topographical features, and antioxidant activity. After enzyme treatment, the ferulic acid (FA) content in AX was reduced from 7.30 to 5.48 µg FA/mg polysaccharide, and the molecule registered a small reduction in radius of gyration (RG), hydrodynamic radius (Rh), characteristic ratio (C∞), and persistence length (q). A slight decrease in α and a small increase in K constants in the Mark–Houwink–Sakurada equation for partially de-esterified AX (FAX) suggested a reduction in molecule structural rigidity and a more expanded coil conformation, respectively, in relation to AX. Fourier transform infrared spectroscopy spectra of AX and FAX presented a pattern characteristic for this polysaccharide. Atomic force microscopy topographic analysis of FAX showed a more regular surface without larger hollows in relation to AX. The antioxidant activity of FAX, compared to AX, was reduced by 30 and 41% using both 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) methods, respectively. These results suggest that feruloyl esterase treatment of AX could offer a strategy to tailor AX chains conformation, morphological features, and antioxidant activity, impacting the development of advanced biomaterials for biomedical and pharmaceutical applications.

Synthesis and Characterization of Lyophilized Chitosan-Based Hydrogels Cross-Linked with Benzaldehyde for Controlled Drug Release

In this study, chitosan-based hydrogels were produced by incorporating three drugs with a different solubility into a polymer matrix. The lyophilized chitosan salt was prepared using an innovative and less-expensive synthetic process by the freeze-drying technique. Firstly, the three drugs (caffeine, ascorbic acid, and 5-fluorouracil (5-FU)) were selected as model drugs to test the in vitro release behavior of the hydrogel. The drugs were solubilized in chitosan salt, lyophilized, and cross-linked with benzaldehyde involving the formation of a Schiff base with (–C=N-) linkage to produce a physical hydrogel. Subsequently, the physicochemical properties of N-benzyl chitosan and lyophilized chitosan salt were evaluated by Fourier-transform infrared (FTIR) spectra, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The intrinsic viscosity of the conventional chitosan was determined by the Mark–Houwink–Sakurada equation. Moreover, the kinetics of hydrogel swelling and drug release were studied by the UV-visible method at physiological conditions (pH = 7.4 at 37°C). The results show that lyophilized N-benzyl chitosan had a maximum swelling ratio of 720 ± 2% by immersion in phosphate-buffered saline solutions (PBS) (pH = 7.4 at 37°C). In vitro drug releases were evaluated in PBS, and the obtained results show that the maximum drug release after 24 h was 42% for caffeine, 99% for 5-FU, and 94% for ascorbic acid. Then, to optimize the cumulative release of caffeine, Tween 20 was added and 98% as a release percentage was obtained. The drug-loading results were investigated with the Korsmeyer–Peppas kinetic model and applied to determine the drug release mechanism.

Dissolution of chitosan nanocrystals in aqueous media of different acidity. Molecular dynamic study

The process of dissolution of chitosan nanocrystals with molecular mass of polymer up to 12.8 kDa in aqueous media of various pH was studied by molecular dynamic simulations with the use of the improved force field GROMOS 56ACARBO_CHT specially developed for the chitosan polymers description. The effect of the media acidity and polymer molecular weight on the dissolution process kinetics has been studied and the regression expressions for kinetic parameters were established. The calculated solution viscosity, Mark–Houwink–Sakurada equation parameters, and pH values of the dissolution beginning are in good agreement with the available experimental data. The uniform/non-uniform distribution of protonated amino groups and hydrogen bonds along the polymeric chains is found to be of key importance parameter for the dissolution process which can be considered as a criterion of dissolution ability.

Size-exclusion chromatography with on-line viscometry of various celluloses with branched and linear structures

We analyzed softwood and hardwood bleached kraft pulps (SBKP and HBKP, respectively), and Japanese cedar (Cryptomeria japonica) celluloses prepared from wood powders using delignification, hemicellulose removal, and dilute acid hydrolysis. For sample preparation, each sample was dissolved in 8% (w/w) lithium chloride/N,N-dimethylacetamide (LiCl/DMAc), after the sample was soaked in ethylenediamine (EDA) and the EDA was exchanged with DMAc through methanol. These solutions were diluted to 1% (w/v) LiCl/DMAc and subjected to size-exclusion chromatography (SEC) combined with multiangle laser light scattering and viscometry analyses. SEC/multiangle laser light scattering and SEC/viscometry use different principles to determine the molecular structures of polymers dissolved in LiCl/DMAc. Both methods showed that SBKP celluloses with high molar masses had branched structures, whereas HBKP celluloses had linear structures as like cotton, bacterial, tunicate, and algal celluloses. Conventionally, viscosity-average molar masses or viscosity-average degrees of polymerization of SBKP and HBKP are obtained by capillary viscometry using a 0.5 M copper ethylenediamine hydroxide (cuen) solution. Because SBKP and HBKP have different cellulose structures (branched and linear molecules, respectively), their viscosity-average molar masses and viscosity-average degrees of polymerization should not be calculated using the same Mark–Houwink–Sakurada equation.

Kuhn–Mark–Houwink–Sakurada Coefficients for Determination of Molecular Parameters of cis-Polybutadiene Rubbers by Gel Permeation Chromatography

Industrial samples of polybutadiene rubbers with a high (95% or more) content of cis-1,4-units obtained on the neodymium-containing catalysts are studied by GPC and NMR spectroscopy (600 MHz). The GPC data obtained under different experimental conditions are analyzed taking into account the molecular weight calculated from NMR data. As a result, the coefficients of the Kuhn–Mark–Houwink–Sakurada equation for the solutions of cis-polybutadiene rubbers in toluene and tetrahydrofuran are refined.

Correction of MHS Viscosimetric Constants upon Numerical Simulation of Temperature Induced Degradation Kinetic of Chitosan Solutions.

The Mark–Houwink–Sakurada (MHS) equation allows for estimation of rheological properties, if the molecular weight is known along with good understanding of the polymer conformation. The intrinsic viscosity of a polymer solution is related to the polymer molecular weight according to the MHS equation, where the value of the constants is related to the specific solvent and its concentration. However, MHS constants do not account for other characteristics of the polymeric solutions, i.e., Deacetilation Degree (DD) when the solute is chitosan. In this paper, the degradation of chitosan in different acidic environments by thermal treatment is addressed. In particular, two different solutions are investigated (used as solvent acetic or hydrochloric acid) with different concentrations used for the preparation of chitosan solutions. The samples were treated at different temperatures (4, 30, and 80 °C) and time points (3, 6 and 24 h). Rheological, Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analyses (TGA) were performed in order to assess the degradation rate of the polymer backbones. Measured values of molecular weight have been integrated in the simulation of the batch degradation of chitosan solutions for evaluating MHS coefficients to be compared with their corresponding experimental values. Evaluating the relationship between the different parameters used in the preparation of chitosan solutions (e.g., temperature, time, acid type and concentration), and their contribution to the degradation of chitosan backbone, it is important to have a mathematical frame that could account for phenomena involved in polymer degradation that go beyond the solvent-solute combination. Therefore, the goal of the present work is to propose an integration of MHS coefficients for chitosan solutions that contemplate a deacetylation degree for chitosan systems or a more general substitution degree for polymers in which viscosity depends not only on molecular weight and solvent combinations.

Determination of the Length, Diameter, Molecular Mass, Density and Surfactant Adsorption of SWCNTs in Dilute Dispersion by Intrinsic Viscosity, Sedimentation, and Diffusion Measurements

A combination of intrinsic viscosity, sedimentation, and diffusion measurements is performed to characterize the structures of single-walled carbon nanotubes (SWCNTs) in dilute dispersion. It allows quantifying the bulk averaged length (L), diameter (d), molecular mass (M), and density (ρ) as well as the surfactant adsorption for SWCNTs. With this approach applied to the SWCNTs processed by sonication, a novel Mark–Houwink–Sakurada equation, [η]c = 1.17M0.33 is recovered. The less than 0.5 exponent is a result of the power-law relationship d ∝ L0.62 caused by the concurrently occurred cutting and exfoliation of SWCNT bundles in the sonication process. An in-depth analysis of the experimentally acquired d and ρ enables a quantification of sodium dodecylbenzenesulfonate (SDBS) adsorption on SWCNTs to reveal the curvature effect on the surface coverage of surfactant adsorption.

Conformation and physical properties of cycloisomaltooligosaccharides in aqueous solution

We studied the conformation and physical properties of cyclic and linear isomaltooligosaccharides in aqueous solution by intrinsic viscosity measurement, small angle X-ray scattering (SAXS) and molecular modeling. We used four cycloisomaltooligosaccharide samples (CIs) with degree of polymerization (DP) 7–10 (CI-7–CI-10) and five linear isomaltooligosaccharide samples (LIs) with DP 7–11 (LI-7–LI-11). The values of α in the Mark–Houwink–Sakurada equation [η]=KMwα for the CI and LI were determined to be 0.50 and 0.78, respectively. The radii of gyration (RG) of CI-7, CI-8, CI-9 and CI-10 determined from SAXS data were 6.7, 6.9, 7.5 and 8.3Å, respectively. The scattering profile of CI-9 compared with those obtained for molecular models indicated that CI molecular chains are less flexible than those for LIs and adopt a rather compact circular conformation.

Experimental and theoretical studies of scaling of sizes and intrinsic viscosity of hyperbranched chains in good solvents

Using a set of hyperbranched polystyrenes with different overall molar masses but a uniform subchain length or a similar overall molar mass but different subchain lengths, we studied their sizes and hydrodynamic behaviors in toluene (a good solvent) at T = 25 °C by combining experimental (laser light scattering (LLS) and viscometry) and theoretical methods based on a partially permeable sphere model. Our results show that both the average radii of gyration (<R(g)>) and hydrodynamic radius (<R(h)>) are scaled to the weight-average molar mass (M(w)) as <R(g)> ~ <R(h)> ~ M(w)(γ)M(w,s) (φ), with γ = 0.47 ± 0.01 and φ = 0.10 ± 0.01; and their intrinsic viscosity ([η]) quantitatively follow the Mark-Houwink-Sakurada (MHS) equation as [η] = K(η)M(w)(ν)M(w,s)(μ) with K(η) = 2.26 × 10(-5), ν = 0.39 ± 0.01, and μ = 0.31 ± 0.01, revealing that these model chains with long subchains are indeed fractal objects. Further, our theoretical and experimental results broadly agree with each other besides a slight deviation from the MHS equation for short subchains, similar to dendrimers, presumably due to the multi-body hydrodynamic interaction. Moreover, we also find that the average viscometric radius (<R(η)>) determined from intrinsic viscosity is slightly smaller than <R(h)> measured in dynamic LLS and their ratio (<R(η)>/<R(h)>) roughly remains 0.95 ± 0.05, reflecting that linear polymer chains are more draining with a smaller <R(h)> than their hyperbranched counterparts for a given intrinsic viscosity. Our current study of the "defect-free" hyperbranched polymer chains offers a standard model for further theoretical investigation of hydrodynamic behaviors of hyperbranched polymers and other complicated architectures, in a remaining unexploited research field of polymer science.

Characteristics of zwitterionic sulfobetaine acrylamide polymer and the hydrogels prepared by free-radical polymerization and effects of physical and chemical crosslinks on the UCST

A zwitterionic sulfobetaine polymer, poly(N,N-dimethyl(acrylamidopropyl) ammonium propane sulfonate) (poly(DMAAPS)), and the hydrogels of this polymer were synthesized by free-radical polymerization in an aqueous redox system using a wide range of monomer concentrations (Cm). The resulting polymers were characterized in terms of polymer yield, intrinsic viscosity, molecular weight, gel fraction, and thermoresponsive phase-transition behavior. Parameters in the Mark–Houwink–Sakurada equation, including the molecular-weight exponent α, were determined for poly(DMAAPS) in 0.1M NaCl aqueous solution. The physical state and transparency of the poly(DMAAPS) samples were strongly dependent on Cm and temperature. At higher values of Cm (i.e. above a critical molecular weight), poly(DMAAPS) became a gel comprising a physically crosslinked network consisting of entangled polymer chains and interchain associations of the zwitterionic groups. The poly(DMAAPS) solutions or gels exhibited a thermoresponsive phase transition with an upper critical solution temperature (UCST). The gels obtained were completely soluble in aqueous NaCl solution at ambient temperature as well as in water at temperatures above UCST. The effects of molecular weight, chemical crosslink density and copolymerization on the UCST were also elucidated.

Fractional Separation and Estimation of Mark-Houwink-Sakurada Equation Parameters for Gluten

Fractional separation of gluten using the fast protein liquid chromatography (FPLC) and a numerical method for determination of Mark-Houwink-Sakurada (MHS) equation were studied. With 1% SDS buffer as solvent, the gluten was disassembled into two components: SDS soluble (SDS-S-G) and SDS insoluble gluten proteins (SDS-IS-G). The average molecular weight (Mn, Mw and Mz) and intrinsic viscosity [η] were measured by the multi-angle laser light scattering (MALLS) in conjunction with a size-exclusion chromatography (SEC) and viscosimetry. MHS equations for SDS soluble gluten and SDS insoluble gluten proteins were established as: (SDS-S-G) [η]=1.7459×10-2Mv0.6933=1.7459×10-2qMHSMw0.6933=1.6677×10-2Mw0.6933 (SDS-IS-G) [η]=7.5682×10-3Mv0.7323=7.5682×10-3qMHSMw0.7323=7.2079×10-3Mw0.7323 where qMHS was the polydispersity correction factor.

Synthesis and properties of a deuterated phenolic resin

A highly deuterated novolac-type phenolic resin was prepared by polycondensation of deuterated phenol and formaldehyde using oxalic acid as an acid catalyst. The polycondensation of deuterated monomers and the formation of the highly deuterated phenolic resin were confirmed by the gel permeation chromatography, IR, and 1H NMR analyses. With the exception of hydroxyl groups, the degree of deuteration was estimated to be more than 98%. The polymer conformation in THF solution was evaluated by the scaling exponent of the Mark–Houwink–Sakurada equation. The exponent of the deuterated phenolic resin is 0.26 in THF at 40 °C and is close to that of a nondeuterated phenolic resin, which suggests that phenolic resins behave like a compact sphere irrespective of deuteration. The curing behavior of the deuterated phenolic resin with hexamethylenetetramine was confirmed by differential scanning calorimetry analysis. The cured highly deuterated phenolic resin exhibits a lower incoherent neutron scattering background than that of the nondeuterated phenolic resin, which suggests that the former is suitable for matrix resins with low incoherent backgrounds for small-angle neutron scattering studies of thermosetting resins. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.

Intrinsic viscosity–number average molecular weight relationship for poly(1,4‐butylene adipate) diol

AbstractThe relationship between number average molecular weight (Mn) and intrinsic viscosity ([η]) was studied for poly(1,4‐butylene adipate) diol (PBAD) in tetrahydrofuran, toluene, and ethyl acetate at 25°C. Thus, a series of PBAD samples were prepared by polymerization between 1,6‐adipic acid and 1,4‐butanediol. The values of Mn for the samples were determined by end‐group analysis as well as by ebulliometry, and the average difference of Mn between the two analysis ways was about 2.69%. The Mark–Houwink–Sakurada equations for PBAD were obtained to relate [η] with Mn in the range of 1900–10,000. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The influence of mono and divalent cations on dilute and non-dilute aqueous solutions of sodium alginates

A broad study of the viscous behavior of three different sodium alginates in dilute and non-dilute solution in the presence of different electrolytes has been performed. In dilute solutions, we have determined the molecular weight of three different samples of sodium alginate from the same source through the Mark–Houwink–Sakurada equation. We have confirmed for the three chains the Pals–Hermans relation in a wide range of ionic strength. The quality of the solvent in this range of ionic strength has also been studied. For non-dilute systems, we have evaluated the behavior of alginates not only in salt-free conditions but also with the addition of monovalent and divalent cations. The transition from Newtonian to non-Newtonian behavior and the variation of the viscosity have been found to be profoundly affected by the addition of these electrolytes.

Preparation and characterization of melamine–formaldehyde–polyvinylpyrrolidone polymer resin for better industrial uses over melamine resins

AbstractMelamine–formaldehyde–polyvinylpyrrolidone (MFP) polymer resin was prepared with 1 : 16 : 1 ratios of melamine, formaldehyde (CH2O), and polyvinylpyrrolidone amounts, respectively, by condensation polymerization at 6.9 pH. Structures were determined with IR, 1H‐NMR, and 13C‐NMR spectroscopies. Chemical shifts (δ, ppm) were analyzed with singlet at δ 4.5, duplet from 3.13 to 3.17 and a quartet at 1.5 to 2.2 ppm for methylene (CH2) bridging group, pyrrolidone, and polyvinyl constituents. The 3389.25, 1290.38, and 1655.28 cm−1 stretching frequencies of N, CH and COO groups, respectively, were noted on FTIR spectrum. The CN melamine units reacted with CH2O to adjoin with polyvinylpyrrolidone (PVP). An average viscosity molecular weight ($\bar{M}$v) 57,000 g mol−1 was obtained with Mark–Houwink–Sakurada equation. The chemical shift of N(CH2O)2Cpyrrolidone ring on 13C‐NMR spectra was shifted toward lower magnetic field at 175.18 ppm. The resin was partially miscible with water thereby densities and viscosities of aqueous solutions were measured at 298.15 K temperature. It showed higher densities and viscosities than those of water. The resin developed exceptionally higher adhesive strengthen when its 62.29‐μm uniform thin film was applied on surfaces of wooden strips. The resin showed micellar behavior at about 0.009 g/100 mL aqueous solution. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Preparation and Characterization of Enzyme-Modified Konjac Glucomannan/Xanthan Blend Films

Enzyme-modified konjac glucomannan (KGM) and xanthan blend films have been prepared and characterized. Enzymatic hydrolysis of purified KGM by β-mannanase yielded samples of various weight-average molecular weight (M w) that were determined by size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS) and calculated using the established Mark–Houwink–Sakurada equation [η] = 4.07 × 10−4 M w 0.733. KGM degradation products were blended with xanthan for preparation of films that were used in orthogonal-designed experiments. These films were characterized in terms of their structures, thermal stability, crystallinities and mechanical properties. The results of Fourier transform infrared spectroscopy indicated that, after blending, there was strong intermolecular interaction caused by hydrogen bonds between xanthan and KGM hydrolysates. This phenomenon was more marked at lower M w of KGM. The thermal stability of the blend films determined by differential scanning calorimetry was higher with increasing KGM molecular weight. The degrees of crystallinity characterized by X-ray diffraction (XRD) decreased with the increasing content of non-degraded KGM. Mechanical properties of the polymer blends including the tensile strength and elongation rate were also correlated to M w of KGM. The tensile strength achieved a maximum at 10.25 MPa with KGM of M w = 4.25 × 105 and the elongation rate reached a maximum value of 89.5% with KGM of M w = 8.95 × 105. These results were directly attributed to intermolecular interactions between xanthan and KGM, and this synergistic behavior led to good physicochemical and mechanical performance of the blended films.

Effects of γ-irradiation on molar mass and properties of Konjac mannan

Konjac mannan (KM) is a water-soluble glucomannan with high molar mass. Here, the effects of γ-irradiation on the structure of KM, its viscosity, molar mass distribution and the state of sorbed water were studied after irradiation at reduced pressure. These changes were investigated using ESR, FT-IR, UV, viscometer, SEC–MALS and DSC. Free radical yields increased with absorbed dose. Irradiation led to chain scission, but introduced no significant new chemical groups into the structure, apart from a small increase in content of carbonyl groups. The intrinsic viscosity, molar mass and radius of gyration decreased rapidly with increasing dose up to 10 kGy and then at a slower rate. The Mark–Houwink–Sakurada equation for the KM gave [ η]=5.30×10 −4 M 0.78. The α value showed that KM molecules are solvated in the form of random coils in water. There are three types of sorbed water in irradiated KM as in the original KM. There is no significant change in water binding ability for KM with M W greater than 2×10 5.

Solution properties of triphenylsilyl cellulose

AbstractFive samples of triphenylsilyl cellulose (TPSC) are characterized in solution by osmometry, viscometry, and size exclusion chromatography. The isolated and purified cellulose ethers are prepared in a N,N‐dimethylformamide and pyridine medium under heterogeneous starting conditions and a nitrogen atmosphere by silylation of activated celluloses with triphenylchlorosilane at 115–120°C. TPSCs are characterized by their polydispersities and degrees of substitution by osmometry and viscometry in various solvents. The Mark–Houwink–Sakurada equation coefficients are evaluated in 1,1,1‐trichloroethane, chloroform, and o‐xylene at 30°C and in o‐xylene over a temperature range of 30–70°C. Values of 2.12–2.18 are obtained for exponent a. This indicates, in combination with low values of the preexponential factor (on the order of 10−12), strong stiffness of the macromolecular chains. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1257–1261, 2007