Side-chain Copolymers Research Articles

Precursors of hydrophilic polymers, 7. Potentiometric properties and structure of copolymers of 2‐dimethylaminoethyl methacrylate

AbstractThe study concerns the potentiometric behaviour of statistical copolymers of 2‐dimethylaminoethyl methacrylate with 2‐hydroxyethyl methacrylate, acrylamide, methacrylamide, 2‐methacryloyloxyethyltrimethylammonium methylsulfate, and of copolymers arising by the partial quaternization of poly(2‐dimethylaminoethyl methacrylate) with methyl iodide in various water‐ethanolic solutions. The potentiometric properties of poly(4‐dimethylaminobutyl methacrylate) and poly(6‐dimethylaminohexyl methacrylate) are also reported. The course of modified titration curves and the differences between pK0 values of copolymers and pK values of low‐molecular weight model compounds are discussed. Side chains of copolymers of 2‐dimethylaminoethyl methacrylate have a cyclic conformation (similarly to the homopolymer); the carbonyl and amine group interact with each other. Copolymers formed by the partial quaternization of poly(2‐dimethylaminoethyl methacrylate) with methyl iodide in a water‐ethanolic medium (Menshutkin's reaction) have a block structure, which suggests a zip mechanism of the quaternization reaction.

Liquid Crystalline Side Chain Polymers Derived From Poly-acrylate, Poly-methyacrylate and Poly-α-chloroacrylate

Abstract Interest in liquid crystalline side-chain polymers has grown tremendously in recent years because of their theoretical aspects and their potential applications. Over the past few years, a considerable research effort has been made in electro-optic display using nematic or smectic. A mesogenic side-chain polymers. On the other hand, non linear optical effects have been obtained with a nematic side-chain copolymer doped with a molecule exhibiting an extremely large molecular hyperpolarizability β and poled with a D.C. electricfield.

Fate of N-(2-hydroxypropyl)methacrylamide copolymers with pendent galactosamine residues after intravenous administration to rats

N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymers bearing galactosamine residues accumulate in the liver after intravenous administration to rats (Duncan, R., Kopec̆ek, J., Rejmanová, P. and Lloyd, J.B. (1983) Biochim. Biophys. Acta 755, 518–521). In this study HPMA copolymers bearing pendent galactosamine residues (1.0–11.6 mol%) were injected intravenously intor rats and their rates of blood clearance and liver accumulation were measured. A level of substitution of 4 mol% was found to be sufficient to cause substantial deposition in the liver 30 min after administration. The most highly substituted polymer (11.6 mol%) was directed rapidly to the liver, 80–90% being recovered there less than 10 min after administration. Separation of liver into hepatocytes and non-parenchymal cells indicated that polymer was largely associated with the hepatocytes, and density-gradient subcellular fractionation of liver at various times after administration confirmed that polymer was internalized by liver cells and transported, with time, into the secondary lysosomes. Experiments using isolated rat hepatocytes indicated that HPMA copolymers with high galactosamine content have higher affinity for the hepatocyte plasma membrane. HPMA copolymers containing galactosamine and in addition glycylglycyltyrosianmide side-chains were used to demonstrate release of a drug analogue across the lysosomal membrane. These polymers were radioiodinated and, following intravenous administration to rats, the liver lysosomes were isolated and incubated at 37°C in 0.25 M sucrose. Radioactivity was released from the lysosomes faster than the lysosomal enzyme arylsulphatase, an observation that indicates intralysosomal hydrolysis of the copolymer side-chain with subsequent passage of low molecular weight degradation product across the lysosomal membrane.

Widely-Spaced Comb-Like Polymers Having Fluoroalkyl Side Chains

An alternating copolymer of butadiene and a fluoroalkyl methacrylate If and its hydrogenated copolymer IIf were synthesized and identified. We designated these copolymers as widely-spaced comb-like polymers as we did the alkyl side chain copolymers in our previous paper [Polym. J., 15, 891 (1983)]. The fluoroalkyl methacrylate homopolymer IIIf is a brittle plastic but If and IIf are extensible elastomers. Although IIIf is soluble in benzotrifluoride only when warmed, If and IIf are soluble at room temperature. The cast films of If, IIf, and IIIf showed the same contact angles of water or n-alkane droplets. Differential scanning calorimetry study demonstrated the crystallization of the fluoroalkyl side chains of If and IIf in spite of their wide spaces. The fluoroalkyl side chains were found to be crystallizable more easily than the alkyl side chains of the same carbon atom numbers.

Dynamic relaxation behavior of copolymers of n‐butyl methacrylate with n‐butyl acrylate and of 2‐hydroxyethyl methacrylate with ethyl acrylate, n‐butyl acrylate, and dodecyl methacrylate

AbstractThe effect of the α‐methyl group on the mobility of the main and side chains of methacrylateacrylate copolymers has been investigated. Poly(ethyl acrylate) shows a small secondary loss maximum (attributed to the rotation of COOR side chains) at 145 K, while in the case of poly(n‐butyl acrylate) this relaxation process is smeared out or possibly absent. On the contrary, poly(n‐butyl methacrylate) and poly(2‐hydroxyethyl methacrylate) exhibit secondary relaxations at about 278 and 301 K, respectively. From the dynamic mechanical response spectra of methacrylate‐acrylate copolymers one can see that the removal of the α‐methyl group causes a qualitative change in the molecular mechanism of the secondary relaxation, presumably as a consequence of the different participation of the main chains. The existing data, however, are insufficient to quantify these differences. The low‐temperature relaxation attributed to internal motion within the side groups is not distinctly affected by the presence of α‐methyl groups. If both components of the copolymer display the low‐temperature relaxation (above 77 K), the loss maxima preserve their identity to a large extent. The effect of copolymer composition on the main (glass) transition temperature has been described by means of a one‐parameter equation.

Design of synthetic copolymer side-chains to facilitate their degradation in lysosomes

Design of synthetic copolymer side-chains to facilitate their degradation in lysosomes

The effect of solvents on asymmetric induction cationic copolymerization of l‐menthyl vinyl ether with indene

AbstractCationic copolymerization of l‐menthyl vinyl ether (l‐MVE) with indene (IN) was carried out in several solvents with BF3OEt2 as catalyst at 0°C. The solvents used in this study were selected toluene (Tol), chloroform (CHCl3), chlorobenzene (BzCl), 1,2‐dichloroethane (EtCl2), and nitrobenzene; (BzNO2)/Tol = 65/35 mixture solvent. l‐Methyl residue, which is an optically active side chain of copolymer produced by cationic copolymerization, was removed with dry hydrogen bromide gas by ether cleavage reaction. The copolymer [vinyl alcohol(VA)–lN], produced by the ether cleavage reaction, also showed optical rotation. From this result, therefore, it was concluded that asymmetric induction takes place in the copolymer main chain. The efficiency of asymmetric induction was determined by the measurement of optical rotation of VA–IN copolymer after the ether cleavage reaction. The efficiency of asymmetric induction in the copolymer main chain developed from the variation on polymerization solvents; the order was Tol > EtCl2 > BzCl > CHCl3 > BzNO2/Tol (65/35) mixture solvent.

Radical copolymerization of optically active l‐menthyl vinyl ether with maleic anhydride, dimethyl maleate, and dimethyl fumarate

AbstractThe copolymerizations of l‐menthyl vinyl ether (l‐MVE) with the monomers, that is, maleic anhydride (MAn), dimethyl maleate (DMM), and dimethyl fumarate (DMFu), were undertaken to obtain optically active copolymers. The optically active l‐menthyl group in the side chain of copolymers was removed by the ether cleavage reaction with dry‐hydrogen bromide gas. The ethercloven copolymers were still optically active. Hence it was concluded that asymmetric carbon atoms were introduced into the copolymer main chain, the reason given being that l‐MVE and comonomers (MAn, DMM, and DMFu) made the stereoselective charge‐transfer complex one another and copolymerized stereospecifically. From the results of the measurements of optical rotatory dispersion (ORD) and circular dichroism (CD) for copolymers before and after the ether cleavage reaction, the mode of bond opening for α,β‐substituted monomers (MAn, DMM, and DMFu) was discussed and the microstructures of copolymers were prepared.

Preparation of soapless latexes by sonification of starch‐based poly(isoprene–co–acrylonitrile) graft reaction mixtures

AbstractGraft copolymerization of isoprene (IP) and acrylonitrile (AN) onto gelatinized starch (S) and cationic starch having quaternary amine functionality through cerium(IV) initiation gave grafted side chains of poly(IP–co–AN). Grafts of various compositions are obtained by controlling the amounts and ratios of monomers added to starch. IP alone does not homograft onto gelatinized starch at 25° or 50°C by cerium(IV) initiation and requires the presence of an “initiator–monomer” such as AN to obtain copolymer side chains. Although cografting of IP and AN onto starch depends on AN to initiate radical chains, the ratio employed of the two monomers is critical for graft polymerization to occur. For example, at a molar ratio of IP to AN of 1 or greater, little polymer was produced; at molar ratios in the range of 0.4 to 0.67, considerable amounts of polymer were produced; and at a molar ratio of 0.13 or less, polymerization of AN was greatly retarded. Concentration of HNO3 in the cerium(IV) reagent and reaction temperature also influence the grafting reaction. Lower HNO3 concentrations favor grafting at 50°C, while higher acid concentrations favor grafting at 25°C. Starch graft reaction mixtures were sonified at 20 kHz to form latexes that air dry to clear pliable films. Poly(IP–co–AN) obtained by acid hydrolysis of the starch portion of the grafts failed to dissolve in either dimethylformamide or benzene, thus indicating presence of crosslinks. S–g–poly(IP–co–AN), having about one third starch and grafted side chains averaging about 2 parts polymerized IP per part of polymerized AN, was masticated on steel rolls at 100°C to a tough pliable film which was subsequently vulcanized to a rubber.

Effect of the length and structure of the side chain of soluble copolymers of the methacrylamide type on the mobility of the spin label bonded to the chain end

AbstractResults are reported obtained by the ESR study of the mobility of spin labels bonded at the side‐chain ends of copolymers of the polymethacrylamide type. The correlation times, γ, characterizing the mobility of the spin label were determined by analyzing the EPR spectra of 1% methanolic solutions of copolymers. The log γ vs 1/T dependences within the temperature interval 233‐313 K studied are linear and are characterized by the same activation energy, Ea = 3 kcal/mole (12.5 kJ/mole), for both types of the side chains. The mobility of the spin label bonded at the end of the side chain of the oligoglycine type is lower than that of the spin label bonded at the end of the equally long side chain of the methylene type.

The Effect of a Method of Dissolution of Graft Copolymer of Polyacrylonitrile and Poly(Methyl Acrylate) on Drawability and Properties of Spun Fibers

It was found that dissolution of the graft copolymer has an effect on drawability and other properties of fibers spun from this graft copolymer. The resistance to double bending and abrasion resistance are considerably decreased with the increase of the dissolution temperature. The breaking properties were not greatly changed. The maximum loop and knotted yarn strength was reached when the polymer was dissolved by heating. These values are 100% and 99% of the original, respectively—higher than those obtained from PAN and PANM. The presence of 5% PMA in the side chains of the graft copolymer increased the flexibility of these chains. This is evident from the decrease of the initial modulus of elasticity from the values obtained for PANM and PAN.

Analytische eigenschaften von hydrophilen glykolmethacrylat-polymeren mit chemisch gebundenem 8-oxychinolin

8-Hydroxyquinoline, bound to the azo group and the flexible side chain of a hydrophilic macroporous copolymer of glycoldimethacrylate and glycolmono methacrylate, possesses high selectivity for heavy metal ions. The exchange capacity of the resin is about 0.2 mmole Me g −1 for heavy metal ions. Sorption equilibrium is complete after 5–10 min. Partition coefficients for 10 metal ions were determined as a function of pH and ionic strength; in the optimal pH range, their magnitudes exceeded 10 4. The exploitation of this material in chromatographic separation of metals, trace analysis, and selective purification of concentrated salt solutions, is discussed.

Circular dichroism study of poly( l-tyrosine), poly( l-glutamic acid) and of random and sequential copolymers of l-glutamic acid and l-tyrosine in trimethylphosphate

Random and sequential copolypeptides containing l-glutamic acid and l-tyrosine, as well as poly( l-tyrosine) and poly( l-glutamic acid) were investigated by means of c.d. spectroscopy in trimethylphosphate as solvent. In random copolymers, variation of ellipticities at 202.5 and 230 nm versus tyrosyl content follows a smooth curve, without any sharp change. This led to the conclusion that poly( l-tyrosine) α-helix is right-handed. From c.d. studies on sequential copolymers we were able to recognize that the 230 nm contribution of tyrosyl side chains is closely related to the array in which tyrosyl residues are arranged in the chain. For instance, it was found that ( n, n + 2) and ( n, n + 3) pairings of tyrosyl side-chains in (Tyr-Glu) n and (Glu-Tyr-Glu) n respectively, were poorly effective, while the ( n, n + 4) pairing in (Glu-Glu-Tyr-Glu) n is more. However, the strongest contribution at 230 nm was observed on the alternating-páirs copolymer (Glu-Tyr-Tyr-Glu) n . This result suggests a new conformational arrangement of tyrosyl side chains in sequential copolymers, as well as in poly( l-tyrosine) and other aromatic polypeptides, based on a regular pairing of the aromatic groups, arranged in two contiguous superhelices.

Trans→cis photoisomerization of the stilbene residues in the side chains of copolymers from 2‐hydroxyethyl methacrylate and monomer containing stilbene residue

AbstractThe rate of the trans→cis photoismerization of the stilbene residue was compared in the copolymer 3 from 2‐hydroxyethyl methacrylate (1) and trans‐N‐4‐(4‐nitrostyryl)phenylmethacrylamide (2a) with its low molecular weight analogue trans‐N‐4‐(4‐nitrostyryl)phenylisobutyramide (2b) in methanol, 2‐ethoxyethanol and in the binary solvents propanol/water and tert‐butyl alcohol/water. It was observed that the trans→cis photoisomerization of the stilbene residues was more rapid at 20°C in the side chains of the copolymer than for 2b in most solvents. This result may be interpreted on the basis of the quantum yield dependence for the trans→cis isomerization on the polarity of the medium where the isomerization takes place. Acceleration of the trans→cis isomerization of the stilbene residues in the side chains of the copolymer results from a decrease in the polymer microenvironment polarity as compared to the polarity of the solvent itself. This interpretation is supported by direct measurement of the polarity of the polymer chain microenvironment, based on the Kosower semi‐empirical polarity scale. The course of the trans→cis isomerization of 2b and 3 does not obey the equilibrium, first‐order reaction for all the solvents mentioned. The effect of preferential sorption of one of the components in binary solvents on the polymer coil and the effect of temperature on the photochemical trans→cis isomerization are discussed in connection with the experimental results.

Consequences of the Excited Volume Effect on the Rate of Reactions Involving Two Randomly Coiled Polymer Chains. II. Hydrolysis of Phenyl Ester Groups in Side Chains of Acrylamide Copolymers in the Presence of Acrylamide Copolymers Carrying Pyridine Residues

Consequences of the Excited Volume Effect on the Rate of Reactions Involving Two Randomly Coiled Polymer Chains. II. Hydrolysis of Phenyl Ester Groups in Side Chains of Acrylamide Copolymers in the Presence of Acrylamide Copolymers Carrying Pyridine Residues

Synthesis of cellulose graft copolymers with mixtures of N‐vinyllactams and vinyl monomers

AbstractSynthesis of cellulose graft copolymers with mixtures of N‐vinyllactams (VL) and vinyl monomers (VM), the definition of the copolymer composition of the grafted chain, coefficients of relative monomers reactiveness, solubility, characteristic viscosity, and the effect of the initial monomer ratio on the obtained products properties are reported.N‐vinylpirrolidone, N‐vinylcaprolactam, and methylmethacrylate butylmethacrylate, acrylonitrile, and β‐hydroxyacrylate glycidic ether were used in the investigations as well as preparations of cotton fibers, fibers of diacetylcellulose, and fibers of viscose staple rayon.VL and VM were grafted onto cellulose in the oxidative‐reductive systems of bivalent ferrous and hydrogen peroxide at various molar ratio (0.1:0.9; 0.25:0.75; 0.5:0.5; 0.75:0.25; 0.9:0.1). The VL‐VM copolymer side chains were hydrolytically isolated from the grafted part of cellulose. The values of rVL and rVM were plotted as those of rVL and rVM for the static polymerization. It is found that the composition of the grafted cellulose side chains was identical with that of the copolymers, which have been obtained by the bulk method. The copolymers solubility remained the same after the grafted cellulose chain was isolated by the classic method of copolymerization in the absence of cellulose.The graft copolymers were identified by IR spectra. The mechanism of the graft copolymerization is given for all the abovementioned monomers and cellulose.