Intrinsic Viscosity Of Polymer Research Articles

Quantitative assessment of polymer molecular shape based on changes in the slope of the Mark‐Houwink plot derived from size‐exclusion chromatography with triple detection

AbstractA new approach is presented for gaining additional insights from the molecular weight distribution and intrinsic viscosity of polymers as obtained using size‐exclusion chromatography in combination with refractive index, viscometry, and multiangle light scattering detectors. The approach allows for a more quantitative interpretation of the Mark‐Houwink plot by assessing the variation of the slope as a function of molecular weight. No prior information on the inter‐ and intramolecular interactions of the polymer is needed. The proposed curvature parameter can be correlated to the structural and chemical properties (e.g., branching, composition, randomness) of the polymer. The influence of the covered molecular weight interval and the sample concentration on the precision of the method was studied. This new workflow can be utilized to assess the effect of the solvent system and conditions on the solvation behavior of polymers. To evaluate the applicability of the workflow, three case studies have been performed, including an analysis of ethylene‐propylene‐diene monomer, cellulose ether, and polyamide‐4,10 samples. In addition, an open‐access tool is provided, to aid polymer researchers in incorporating this approach in their work. The developed method can be used to quickly investigate whether an industrial polymer batch contains unwanted branched species or exhibits particular solvation behavior.

Studies on Biodegradable Polyether Ester Urethanes from Natural Resource and their Application in Coatings

Polyether ester urethanes from natural resources have wide range of applications in coating and paint industries. Peanut is a major crop of Gujarat especially of saurashtra region (India). Peanut oil contains highly unsaturated mono acids such as linoleic acid and oleic acid which can be used for the synthesis of polyether ester urethanes. These monoacids have been allowed to react with glycerol in presence of weak acid (Acetic acid) and strong acid (Sulfuric acid) as catalyst to prepare polyether ester polyols (PEEP) which were further reacted with isophorone diisocyanate to synthesize polyether ester urethane (PEEU). Physico-chemical properties of polyether ester polyol were determined by measuring acid value and intrinsic viscosity of polymers. For determination of molecular weight and structure GPC, FTIR and NMR spectroscopy were used. Polyether ester urethanes have been used for coating and casting purposes. Thermal stability of cured product has been determined using thermogravimetric analysis. Mechanical properties of coating like pencil hardness, scratch hardness, adhesion and flexibility have been found out. Being biodegradable in nature, soil degradation test of polyether ester urethanes have been performed. After continuous exposure to moist soil, results show polyether ester urethanes started to degrade after 120 days.

Preparation of PMMA nanolatex via microemulsion polymerization initiated by UV direct radiation at low temperature

By combining the microemulsion polymerization with UV direct initiation, an efficient polymerization method was developed due to its advantages in terms of high polymerization rate and conversion, lower polymerization temperature, high purity polymer. To be more specific, in the absence of initiator and under UV direct radiation, the polymerizations of MMA/Water/emulsifier microemulsion system were successfully accomplished at low temperature (26 ∼ 35°C) and PMMA nanolatex with the average diameter of 9.5 nm and narrow diameter distribution was obtained. The effects of UV intensity, monomer concentration, emulsifier concentration and temperature on polymerization rate and intrinsic viscosity of polymer were researched. The apparent activation energy of the reaction and polymerization kinetics of Rp are obtained as the following: Rp∝[IUV] 1.25[M]1.04[E]−2.57, Ea=14.45KJ/mol.

INTERPHASE DISTRIBUTION OF SOME AMINO ACIDS IN EXTRACTION SYSTEMS BASED ON N-VINYLFORMAMIDE COPOLYMERS

The extraction characteristics of amino acids and mono-amides of acids were studied using copolymers of N-vinylformamide with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole as extractants. Synthesis of water-soluble copolymers was carried out by radical copolymerization in dioxane with thermoinitiation with dinitro-azobisisomoic acid. The distribution coefficients and the degree of extraction of analytes for a single extraction in the presence of a salting out agent are calculated. To determine the representatives of amino acids, the method of capillary electrophoresis was used. The most effective extraction systems for the extraction of amino acids and monoamides of acids are proposed: the intrinsic viscosity of polymers, the concentration of polymer and analyte solution, the ratio of phase volumes, the ratio of the mole fractions of N-vinylformamide to 1-vinyl and 1-methacryloyl-3,5-dimethylpyrazole. The results of the most effective interfacial distribution of lysine between a water-salt solution and an extractant are presented, which is a copolymer of N-vinylformamide with 1-methacryloyl-3,5-dimethylpyrazole. The concentration of the copolymer and the ratio of the volumes of equilibrium phases at which the maximum degree of lysine extraction is reached are established. A copolymer of N-vinylformamide with 1-vinyl-3,5-dimethylpyrazole is used for simultaneous extraction of cystine, asparagine and glutamine. The established extraction characteristics allowed a successful separate determination of the amino acid cystine and monoamides (asparagine and glutamine) in a joint presence in an aqueous solution. When choosing the conditions for separate electrophoretic determination of amino acids, the optimal composition of the buffer solution, the type and concentration of the micelle was found. The dependence of the structure of the analytes on their interphase distribution was established, and the complexing power of the copolymers of N-vinylformamide with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole was revealed with respect to the representatives of amino acids. The extraction systems used on the basis of N-vinylformamide copolymers are distinguished by ecological and economic expediency, good metrological indices.

Viscoelasticity of poly(ethylene glycol) in aqueous solutions of potassium sulfate: a comparison of quartz crystal microbalance with conventional methods

The viscoelasticity of poly(ethylene glycol) (PEG) in aqueous solutions with different concentrations of potassium sulfate (K2SO4) was studied by quartz crystal microbalance with dissipation (QCM-D), after coating a rigid supported lipid bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine on the silicon oxide substrate. The obtained viscoelastic properties of PEG in K2SO4 solutions agree well with the Zimm model predictions for linear polymer chains. With increasing K2SO4 concentration, the excluded volume exponent ν of PEG decreased from 0.565 in water to 0.55 in 0.19 mol/L K2SO4, and 0.50 in 0.43 mol/L K2SO4. The solvent quality gradually worsened for PEG with increasing K2SO4 concentration, which was verified by decreases in the polymer intrinsic viscosity and the corresponding Mark–Houwink exponent. The high-frequency characteristic of QCM-D makes it possible to directly study the viscoelasticity of polymer solutions in a low-viscosity solvent, which is complementary to conventional rheometers working at low frequency. Viscoelasticity of PEG in aqueous solutions containing different concentrations of K2SO4 was studied by QCM-D, after coating a rigid supported lipid bilayer on the silicon oxide substrate. The obtained viscoelastic properties of PEG in K2SO4 solutions agree well with the Zimm model predictions for linear polymer chains. The gradual worsening of solvent quality by adding K2SO4 to aqueous PEG solutions is demonstrated by the obtained excluded volume exponents via QCM-D and the conventional intrinsic viscosity measurements.

A Study of the Viscosity Characteristics of Chitosan Solutions in the Presence of Organic Cosolvents

The effect of organic cosolvents (ethanol and isopropanol) on the viscosity characteristics of acetic acid aqueous solutions of chitosan is studied. Sorption and deformation–strength properties, as well as resistance to the process of enzymatic degradation of materials obtained from solutions, are determined. It is shown that the introduction of cosolvents into the chitosan–1% acetic acid system is accompanied by a consistent decrease in the intrinsic viscosity of polymers. It is found that, in the presence of cosolvents, at concentrations below the crossover concentration, chitosan molecules exist as systems of interacting (aggregated) macromolecules rather than isolated macromolecular coils. A change in the conformation of chitosan and the type of macromolecular aggregates in acetic acid solutions in the presence of cosolvents leads to a number of consequences: polymer units become less accessible to an enzyme preparation, the rate of enzymatic degradation decreases, and mechanical characteristics of film materials change.

Lattice Boltzmann model for three-phase viscoelastic fluid flow.

A lattice Boltzmann (LB) framework is developed for simulation of three-phase viscoelastic fluid flows in complex geometries. This model is based on a Rothman-Keller type model for immiscible multiphase flows which ensures mass conservation of each component in porous media even for a high density ratio. To account for the viscoelastic effects, the Maxwell constitutive relation is correctly introduced into the momentum equation, which leads to a modified lattice Boltzmann evolution equation for Maxwell fluids by removing the normal but excess viscous term. Our simulation tests indicate that this excess viscous term may induce significant errors. After three benchmark cases, the displacement processes of oil by dispersed polymer are studied as a typical example of three-phase viscoelastic fluid flow. The results show that increasing either the polymer intrinsic viscosity or the elastic modulus will enhance the oil recovery.

Microwave-assisted synthesis of isosorbide-derived diols for the preparation of thermally stable thermoplastic polyurethane

In order to prepare thermally stable isosorbide-derived thermoplastic polyurethane, the synthesis of two new chiral exo–exo configured diols, prepared from isosorbide, and two types of diphenols (bisphenol A and thiodiphenol) was described. The synthesis conditions were optimized under conventional heating and microwave irradiations. To prove their suitability in polymerization, these monomers were successfully polymerized using 4,4′-diphenylmethane diisocyanate (MDI) and hexamethylene diisocyanate (HDI). Both monomers and polymers have been studied by NMR, FT-IR, TGA, DSC; intrinsic viscosity of polymers has also been determined. The results showed the effectiveness of the synthetic strategy proposed; moreover, a dramatic reduction of the reaction time and an important improvement of the monomers yield using microwave irradiation have been demonstrated. The monomers, as well as the polymers, showed excellent thermal stability both in air and nitrogen. It was also shown that the introduction of sulphur in the polyurethane backbone was effective in delaying the onset of degradation as well as the degradation rate.

High molecular weight polyacrylamide nanoparticles prepared by inverse emulsion polymerization: reaction conditions-properties relationships

High molecular weight polyacrylamide (PAM) nanoparticle dispersions are products with wide application possibilities, the most important of which is in petroleum industry such as drilling fluid and flooding agent in enhanced oil recovery. For that aim, it is necessary to achieve complete control of the final dispersion and polymer properties during the synthesis step. In this work, PAMs were synthesized by inverse emulsion polymerization of aqueous acrylamide solution in cyclohexane in the presence of emulsifier mixture of Span 20 and Span 80. We present a comprehensive study of the effects of variation of all important reaction conditions (agitation rate, reaction time and temperature, initiator type and concentration, emulsifier HLB ratio and its concentration, and water to oil ratio) on final monomer conversion, reaction kinetics, polymer intrinsic viscosity and molecular weight, particle size and distribution, and colloidal stability. Finally, the relationships between the reaction conditions and the polymer properties were developed, which allowed determination of the ranges of variation of reaction conditions for optimal PAM properties for the oil industry applications: high molecular weight and intrinsic viscosity, nanosized polymer particles with narrow particle size distribution, and improved colloidal stability of the final dispersions.

Correlating Aggregates Structure with PEL Characteristics Using an Experimental Design Methodology

Aggregation of particles is fundamental for improving the performance of many solid/liquid processes. Aggregation can be induced by different means, one of the most common being based on the addition of polymeric additives, namely polyelectrolytes (PEL). In this work we have studied the flocculation of precipitated calcium carbonate (PCC), used as filler in papermaking, induced by a range of cationic polyacrylamides with different structures, varying in molar mass and degree of branching. The flocculation process was monitored continuously using the LDS technique. Using an experimental design strategy it was possible to produce a model which allows us to relate the aggregates structure, described by the scattering exponent (SE), with the PEL characteristics and concentration (R2 around 79%). The Partial Least Squares (PLS) regression method was selected to perform the regression, given the significant collinearity among the input variables. The results obtained lead us to conclude that the polymer intrinsic viscosity (related with the PEL molar mass and charge density, and supplying information about the volume of the polymer molecule in the solution) and the degree of branching, are the parameters with a stronger influence on the resulting flocs structure. The PLS model developed was successfully validated using an independent data set, which provides confidence on its consistency and prediction accuracy.

Synthesis of High Molecular Weight Cationic Polyacrylamide

Cationic polyacrylamide is a derivative of polyacrylamide, a cationic polymer flocculant which has an excellent effect on sewage treatment. Our existing cationic polyacrylamide are mostly prepared by the Mannich reaction ,which has the shortcomings of more unreacted material, low cationic degree, poor stability, short validity, etc. Therefore, a cationic polyacrylamide has been prepared by aqueous solution.P(DAC-AM) was synthesized by aqueous copolymerization of acrylamide (AM) and DAC using complex initiated system consisted of (NH4)2S2O8,NaHSO3 and V-50. Mass percent of monomer, amount of initiator, content of cation monomer, pH, reaction time et al on the effect of intrinsic viscosity of polymer were discussed. The suitable conditions of synthesis were concluded. Mass concentration of monomers:35%, initiator amount 0.06 %,V-50 amount 0.005%,pH:5.5~6.5,urea concentration 0.1%,EDTA 0.02%,β-dimethylaminopropionitrile concentration 0.03%,reaction time 5~6h,the intrinsic viscosity of product is 13.95dL·g-1.

Kinetics of Inverse Emulsion Copolymerization of Dimethyl Diallyl Ammonium Chloride and Acrylamide

Inverse emulsion copolymerization of DMDAAC with AM has been investigated by the dilatometer technique using the mixture of Span-80 and Tween-80 as the composite emulsifier and 2,2’-azobis (2-methylpropionconidine) dihydro chloride as the initiator. In inverse emulsion copolymerization, the influences of the concentrations of monomers, emulsifier and initiator and initial temperature on polymerization rate and the intrinsic viscosity of polymer have been examined. Its kinetics can be expressed as,. The overall activation energy for the rate of polymerization was determined with a dilatometer as 20.33 kJ/mol over the temperature range 35-55°C.

Intrinsic Viscosity of Polymers: General Theory Based on a Partially Permeable Sphere Model

We present a general theory for the intrinsic viscosity of flexible polymers of arbitrary architecture. The theory is based on a partially permeable sphere model for which we introduce two phenomenological functions, the drag function ξ and the drainage function κ, that are determined by the density profile of the polymer. At the mean-field level, these functions capture the long-range, multibody, accumulative hydrodynamic interactions, that are responsible for the frictional dissipation in and around a polymer. The density profiles for a diversity of chain architectures are obtained by Monte Carlo simulation. Predictions from our theory are in good agreement with experimental data on all the polymer structures examined, ranging from linear, ring, and stars to hyperbranched and dendrimers. The concepts and methods we introduce in this work should be useful for studying other dilute solution frictional properties, such as the self-diffusivity, and provide a convenient framework for understanding the relationship between the molecular architecture and their dilute solution properties.

An experimental design methodology to evaluate the importance of different parameters on flocculation by polyelectrolytes

Aggregation of particles is fundamental for improving the performance of many solid/liquid processes. Aggregation can be induced by different means, and one of the most common is based on the addition of polymeric additives, namely polyelectrolytes. In this work we have studied the flocculation of precipitated calcium carbonate (PCC), which is used as a filler in papermaking, and is induced by a range of cationic polyacrylamides with different structures, varying in molar mass and degree of branching. The flocculation process was monitored continuously using the LDS technique (laser diffraction scattering), which provides information about the size distribution and structure (fractal dimension) of the aggregates, for each sampling instant and, thus, about the kinetic curve for the flocculation process. This information has then been used to produce a model, based on an experimental design strategy, which allows us to relate flocculation efficiency with the PEL characteristics and concentration. The Partial Least Squares (PLS) regression method was selected to perform the regression, given the significant co linearity among the input variables. The results obtained lead us to conclude that the polymer intrinsic viscosity (related with the PEL molar mass and charge density, and supplying information about the volume of the polymer molecule in the solution) and the degree of branching are the parameters with a stronger influence on flocculation efficiency. The PLS models developed were also successfully validated using an independent data set, which provides confidence on their consistency and prediction accuracy. Surface plot of flocculation efficiency (y) against intrinsic viscosity‐IV (X 3 ) and degree of branching of the polyelectrolyte chain (X 1 ). IV and degree of branching are the polymer characteristics with stronger influence on flocculation efficiency. ► Flocculation of calcium carbonate induced by cationic polyacrylamides was studied. ► LDS allowed the construction of the kinetic curves for the flocculation process. ► An experimental design strategy was used to obtain a flocculation efficiency model. ► The model response is mostly dependent on polymer intrinsic viscosity and branching.

The influence of forming conditions on the properties of the fibers made of chitin butyryl‐acetic copolyester for medical applications

AbstractThis work describes the impact of basic parameters of the forming process on the macroscopic structure, sorption properties, and strength of fibers made of chitin butyryl‐acetic copolyester (BOC). Regardless of the chemical structure of chitin BOC and intrinsic viscosity of polymer, solutions used in the spinning industry are non‐Newtonian fluids diluted by shearing without flow boundary. Obtained fibers have a high total pore volume; thus, they may be classified into the group of highly porous fibers. The nature of the porous structure and the total pore volume result in high sorption properties of this hydrophobic material and in very high values of water retention. At the same time, fibers made of chitin derivatives have a good tenacity exceeding 24 cN/tex. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Kinetics of production and characterization of the fucose-containing exopolysaccharide from Enterobacter A47

A fucose-containing exopolysaccharide (EPS) was produced by the bacterium Enterobacter A47 using glycerol byproduct from the biodiesel industry. The analysis of kinetic data suggested a partially growth associated EPS synthesis model. Although the EPS was composed of fucose, galactose and glucose at all cultivation stages, their relative proportion has varied considerably during the run. At the beginning (24h), glucose was the main component (82.4 wt.%), being fucose and galactose minor components (5.0 wt.% and 10.9 wt.%, respectively), while at the end (96 h) it was composed of 26.0 wt.% fucose, 28.9 wt.% galactose and 43.7 wt.% glucose. The acyl groups content and composition have also changed, reaching their maximum content (19.2wt.%) at the end of the run. Moreover, the molecular weight has increased linearly during the run (from 8×10(5) to 5×10(6)). The changes observed in EPS composition and molecular weight have also had an impact upon the polymer's intrinsic viscosity, as shown by its linear increase from 3.95 to 10.72 dL g(-1). The results suggest that the culture might have synthesized at least two distinct EPS, with different sugar composition and average molecular weight, which predominated at different cultivation stages.

Kinetics of dispersion polymerization of dimethyl diallyl ammonium chloride and acrylamide

Dispersion copolymerization of dimethyl diallyl ammonium chloride with acrylamide has been investigated by the dilatometer technique using the mixture of poly(vinylpyrrolidone) and poly(dimethyl diallyl ammonium chloride) as the composite stabilizer and 2,2′-azobis(2-methylpropionconidine)dihydro chloride as the initiator. Monomer reactivity ratios of AM and DMDAAC were determined by the application of Fineman-Ross methods. The analysis of reactivity ratios revealed that DMDAAC is less reactive than AM, and copolymers formed are statistically in nature. The influences of the molar ratio of AM to DMDAAC, concentrations of monomers, stabilizer and initiator, etc. on polymerization rate and intrinsic viscosity of polymer have been examined. The rate of polymerization (Rp) can be represented by \( {R_{\rm{p}}} \propto {[M]^{1.44}},{R_{\rm{p}}} \propto {[S]^{0.39}},{R_{\rm{p}}} \propto {[I]^{0.60}} \). The overall activation energy for the rate of polymerization is 37.38 kJ/mol over the temperature range 35–55°C.Based on the experimental results, the polymerization mechanisms were discussed.

Water‐soluble copolymers. V. Synthesis of low molecular weight amphoteric polyacrylamide by foamed copolymerization

AbstractAmphoteric polyacrylamide of acrylamide, acryloyloxyethyl trimethylammonium chloride, sodium acrylate, and acrylic acid was synthesized by foamed copolymerization. The effects of monomer concentration and composition, initiator concentration and composition, sodium bicarbonate and stabilizer content on the polymer intrinsic viscosity and monomer conversion were examined. The monomer conversion increased with increasing initiator concentration, sodium bicarbonate and stabilizer content. The polymer intrinsic viscosity decreased with increasing initiator concentration. The structure and low molecular weight of the amphoteric polymer were identified by fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC), respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis, characterization, and thermal stability of novel wholly para-oriented aromatic poly(ether-amide-hydrazide)s bearing pendant groups and their corresponding poly(ether-amide-1,3,4-oxadiazole)s

Four novel wholly para-oriented aromatic poly(ether-amide-hydrazide)s containing various pendant groups on their aromatic rings were synthesized from p-aminosalicylic acid hydrazide (PASH) with an equimolar amount of either 4,4′-(1,4-phenylenedioxy)dibenzoyl chloride (1a), 4,4′-(2,5-tolylenedioxy)dibenzoyl chloride (1b), 4,4′-(2-tert-butyl-1,4-phenylenedioxy)dibenzoyl chloride (1c), or 4,4′-(2,5-biphenylenedioxy)dibenzoyl chloride (1d) via a low temperature solution polycondensation reaction. A polyamide-hydrazide without the ether and pendant groups, poly[4-(terephthaloylamino)salicylic acid hydrazide, PTASH, is also investigated for comparison. It was synthesized from PASH and terephthaloyl chloride by the same synthetic route. The polymer intrinsic viscosities ranged from 4.5 to 2.47 dlg−1 in N,N-dimethyl acetamide (DMAc) at 30 °C and decreased with the introduction of the ether and pendant groups into the polymer. All the polymers were soluble in DMAc, N,N-dimethyl formamide (DMF), and N-methyl-2-pyrrolidone (NMP) and their solutions could be cast into flexible films with good mechanical strengths. Further, they exhibited a great affinity to water sorption. Their solubility and hydrophilicity increased with introduction of the ether and pendant groups into the polymer. The prepared polymers could be thermally cyclodehydrated under nitrogen atmosphere into the corresponding poly(ether-amide-1,3,4-oxadiazole)s approximately in the region of 300–450 °C. The introduction of the flexibilizing ether linkages and the pendant groups into the polymer improves the solubility of the resulting poly(ether-amide-1,3,4-oxadiazole)s compared to poly(amide-1,3,4-oxadiazole) free from these groups.

주사슬에 ether-ether-ester 결합을 갖는 액정공중합체의 합성 및 성질

유연한 곁사슬을 가지고 있는 copoly(ether-ether-ester)가 중축합반응에 의하여 합성되었다. 테트라클로로에탄 중에서 측정된 중합체의 고유점성도 값은 0.42~0.78 dl/g을 나타내었다. 합성된 고분자의 구조는 <TEX>$^1H$</TEX>-NMR과 FT-IR에 의하여 조사되었으며, 열적성질과 액정성은 DSC, TGA, POM, XRD에 의하여 측정되었다. 조사된 결과에 의하면 합성된 공중합체들은 모두 단독중합체보다 낮은 용융전이온도를 나타내었으며, 공중합체 내의 비페닐렌 단위의 함량이 60 mol %이상일 때 네마틱액정상이 관찰되었으며, 합성된 중합체의 액정성은 비페닐렌 함량에 의존하였다. Copoly(ether-ether-ester)s having flexible side chain were synthesized by polycondensation. Intrinsic viscosities of polymers were between 0.42 and 0.78dl/g in tetrachloroethane. The polymer structures were investigated by <TEX>$^1H$</TEX>-NMR and FT-IR, and thermal and liquid crystalline properties of polymers were measured by DSC, TGA, POM and XRD. As results of investigations, synthetic copolymers exhibited lower melting temperature than homopolymers. When the biphenylene units contents in copolymer were more than 60 mol %, nematic mesophase was observed, and the mesophase of synthetic polymers was dependent upon biphenylene content.