Pendant Hydroxyl Research Articles

Relationship between the thermodynamic values of two poly(amido-amine)s and their dispersing action on a copper mineral

The interaction between hydrogen and copper ions and two poly(amido-amine)s containing two basic aliphatic nitrogens, two aliphatic nitrogens and two pendent hydroxyl groups, have been investigated by calorimetric techniques. The polymers are adsorbed on the surface of the chalcocite mineral and cause a dispersing effect which has been measured. The action of the two polymers on the copper mineral and the mechanism of adsorption have been explained by considering the species present in solution and the appropriate thermodynamic quantities.

Ultrasonic studies of aqueous solutions of polyvinylalcohol

Ultrasonic absorption and velocity measurements are reported on aqueous solutions of polyvinylalcohol of different molecular weights, degrees of hydrolysis and concentration. The absorption measurements cover a frequency range from 2–1000 MHz and the velocity data a frequency range from 2–200 MHz, the data were obtained over a temperature range from 273 to 333 K. Comparison of the data obtained as a function of the degree of hydrolysis indicate the magnitude of the contributions due to relaxation of the backbone and of the side chain acetyl groups. In the case of the 100% hydrolysed material, the relaxation spectrum is simplified and corresponds to that of motion of the pendant hydroxyl groups. Deviations of the variation of the attenuation with concentration from the ‘ideal’ dilute solution behaviour are ascribed to the effects of polymer-polymer interactions. The magnitude of the volume change associated with polymer-solvent interactions is estimated and discussed.

Polycondensation reaction of dimethyl tartrate with hexamethylenediamine in the presence of various matrices

AbstractThe polycondensation reaction of dimethyl tartrate (DMT) with hexamethylenediamine (HMD) was carried out in dimethyl sulfoxide (DMSO) at 60°C in the presence of various polymer matrices, which were expected to interact with DMT or the resulting polyamide which had pendant hydroxyl groups due to hydrogen bonding. It was found that the rate of polycondensation was enhanced by polymer matrices such as poly(vinyl pyrrolidone) (PVP), Pullulan (polysaccharide) (PF), and poly(vinyl alcohol) (PVA). The rate enhancement became more pronounced with increasing molecular weight of the polymer matrix. When polycondensation in the presence of PVA was carried out in DMSO, a polymer complex was produced. The formation of the polymer complex between the resulting polyamide and PVA during polycondensation was dependent on the concentration of monomers and also on PVA; a gelation of the solution was observed at a concentration of PVA.

Polycondensation of diethyl mucate with hexamethylenediamine in the presence of poly(vinyl pyridine)

AbstractThe polycondensation reaction of diethyl mucate (DEM) with hexamethylenediamine (HMD) was carried out in dimethyl sulfoxide (DMSO) at 60°C in the presence of poly(vinyl pyridine) (P‐VPy) as a matrix polymer, which was expected to interact with DEM or the resulting polyamide which had pendant hydroxyl groups due to a hydrogen bonding. It was found that the polycondensation of DEM with HMD in the presence of poly(4‐vinyl pyridine) (P‐4VPy) produced a polyamide with a higher molecular weight than those in the presence of poly(2‐vinyl pyridine) (P‐2VPy) or in the absence of P‐4VPy. The rate of the polycondensation, however, was rarely enhanced by polymer matrixes such as P‐4VPy and P‐2VPy. During polycondensation in the presence of P‐4VPy a gelation of the reaction mixture was observed when the solution was kept at 30°C for several days. This might be ascribed to the formation of the polymer complex between resulting polyamide and P‐4VPy during the polycondensation.

Synthesis of Polyenamines with Pendant Hydroxyl Groups by Ring-Opening Polyaddition of 5,5′-Oxalylbis(3,4-dihydro-2H-pyran) with Diamines

A new class of polyenamines with pendant hydroxyl groups was synthesized by the ring-opening polyaddition of 5,5′-oxalylbisi(3,4-dihydro-2H-pyran) with diamines through vinyl-ogous nucleophilic substitution. Solution polymerization carried out in alcoholic solvents such as m-cresol at room temperature afforded polymers having inherent viscosities of 0.1–0.27 in quantitative yields. The hydroxyl-containing polyenamines were soluble in a limited number of solvents and had low softening temperatures, below 200°C.

Miscible blends of poly(butylene terephthalate) and the polyhydroxyether of bisphenol A

AbstractMelt blends of poly(butylene terephthalate) (PBT) and the polyhydroxyether of bisphenol A (phenoxy) exhibit excellent transparency above the melting point of PBT as well as for the quenched molded specimens. Dynamic mechanical and calorimetric characterization revealed single and sharp glass transitions intermediate between those for the individual constituents. Increasing phenoxy content in the blends depressed the crystallization rate of PBT due to dilution and viscosity (Tg increase) effects. The apparent miscibility is believed due to the potential specific interactions between phenoxy pendant hydroxyl (proton donor) and the ester carbonyl of PBT (proton acceptor). Heat of fusion results surprisingly show an increase in the degree of PBT crystallinity as the phenoxy content of the blend is increased. No explanation is offered at this point for this unexpected behavior.

Aminolysis Reaction of Reactive Diesters with Amine

Diesters having hydroxyl groups can react with diamines under mild conditions to form polyamides having pendant hydroxyl groups. The reactivity enhancement owing to the hydroxyl group was investigated in terms of the aminolysis reaction of aliphatic or heterocyclic hydroxyl diesters with butylamine. Apparent rate constants could be expressed in the following equation: kobs=k1[BuNH2]+k2[BuNH2]2 The enhancement effect of the hydroxyl group on the aminolysis reaction was interpreted either as the polarity change of the ester carbonyl group, in the case of heterocyclic diesters, or as the intermolecular hydrogen bonding with amine, in the case of aliphatic diesters.

Diisocyanate Vulcanization of 1-Chlorobutadiene-Butadiene Rubber

Abstract TDI-d was found to react quantitatively with hydroxyl group in CB-BR under relatively mild curing conditions to give CB-BR vulcanizates, while AEP afforded vulcanizates having a certain amount of pendent AEP. The latter could be used to increase the network-chain density by postcuring with TDI. This crosslink formation was found to proceed almost quantitatively through the reaction of pendent AEP and hydroxyl groups with equimolar amounts of TDI in CB-BR under suitable curing conditions.

Photoactive polymers containing vanadium: 1. Preparation, characterization and photoreactions

Photoactive polymers have been prepared by reaction of VOQ 2OH (Q = 8-quinolyloxo) with polymers of types A and B carrying pendant hydroxyl groups. Type A was represented by copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate and type B by a copolymer of styrene and p-vinylbenzyl alcohol. The final copolymers are designated VA, VB, respectively. The copolymers were characterized by near u.v.—visible spectra. On irradiation ( λ = 365 nm) the vanadium (IV) chelate VOQ 2 is formed; this is indicated by the u.v.—visible spectral changes, and also by e.s.r. spectroscopy. The infra-red spectra of the copolymers VA, VB show important differences, notably the presence of a strong band near 960 cm −1 (attributable to V=O stretching vibrations) in the former and its absence from the latter. From this and other evidence it is concluded that the vanadium residues have different structures in the two types of copolymer, viz. O=VQ 2OR and (HO) 2VQ 2OR in VA and VB respectively, where R is the remainder of the copolymer molecule. Irradiation ( λ = 365 nm) is considered to bring about scission of VOR bonds in copolymer VA with formation of a macroalkyloxy radical OR. This is consistent with spin-trapping experiments with benzylidene nitrone. On the other hand, photolysis of copolymer VB appears to give radicals identical with those from VOQ 2OH which are most probably OH. The formation of different types of radical on irradiation of copolymers VA, VB is also indicated by spin-trapping observations with nitrosodurene in benzene solution and also the occurrence of photografting when VA (but not VB) is irradiated in a monomer. The photolysis of VOQ 2OH to which we have referred above may provide a convenient source of hydroxyl radicals in non-aqueous solution.

Syntheses of functional condensation polymer. I. Polyesters having pendant functional groups such as hydroxyl, formyl, aldoxime, aminomethyl and hydroxymethyl

AbstractUnsaturated polyesters having pendant functional groups such as hydroxyl, formyl, aldoxime, aminomethyl and hydroxymethyl, have been prepared and characterized, and some of their properties were investigated. Reaction conditions for the epoxidation of unsaturated polyesters and hydrolysis of the epoxy groups in the polyesters were established to control the amount of pendant diol groups. It was possible to incorporate up to 90 mole‐% of formyl side groups into the unsaturated polyester by the hydroformylation with the rhodium catalyst. In addition, the formyl side groups of the modified polyester were converted into hydroxymethyl or aldoxime groups and were then converted to amino groups. The melting points of the modified polyesters decreased with increasing the pendant group content of the polyesters, as expected. Aliphatic polyesters having pendant hydroxyl or amino groups had a high affinity for moisture, which might be ascribed to the participation of the hydrophilic pendant groups in the modified polyesters.

Active polycondensation of diethyl 2,3,4,5‐tetrahydroxyadipate with diamines

AbstractPolycondensation of diethyl 2,3,4,5‐tetrahydroxyadipate with various diamines was carried out in solutions under mild conditions. The polycondensation reaction occurred rapidly even at room temperature in polar solvents such as alcohols, and in aqueous solution a cyclic product was obtained instead of linear polymers although the reaction with diamines was completed within several minutes. Polymers obtained from diethyl 2,3,4,5‐tetrahydroxyadipate were a linear polyamide having pendant hydroxyl groups, which decomposed on heating at around 200°C. A solid‐phase polycondensation of the precursor polyamide yielded a high molecular weight polyamide.

Synthesis of hydrophilic polyamide from L‐tartarate and diamines by active polycondensation

AbstractDimethyl L‐tartarate underwent polycondensation reaction with hexamethylenediamine in solutions at 30°C to form polyamide having pendent hydroxyl groups. Solvents had a great influence on polymer yields and diglyme, tetrahydrofuran (THF) or dimethylsulfoxide (DMSO) were favorable in respect of polymer yields. Solution viscosities of resulting polyamide were as low as 0.1 to 0.2. However, post‐polycondensation of the precursor polyamide at solid phase yielded hydrophilic polyamide having film‐forming ability. The polyamide decomposed at 210°C by heating.

Exchange reactions as a basis of thermopiastic behaviour in crosslinked polymers

AbstractAn attempt has been made to achieve thermoplastic behaviour in a chemically crosslinked elastomer by arranging that the crosslinks should undergo rapid exchange at high temperatures. Natural rubber was chemically modified to give pendent hydroxyl groups which were then used as crosslinking sites to form β‐keto‐ester or malonate crosslinks. The resultant vulcanisates showed high stress relaxation rates in the temperature range 120 to 160°C and some degree of remouldability at 180°C. The incursion of permanent crosslinking prevented quantitative correlation between stress relaxation rates and chemical exchange rates of the crosslinking systems.

Polythiazolines

AbstractPolythioureas having pendant hydroxyl groups were prepared by the polyaddition reaction of bisaminoalcohols and diisothiocyanates. The polythioureas had inherent viscosities in the range of 0.22–1.08 dl/g and gave transparent films by solution casting. These polythioureas were converted to polythiazolines by treatment with poly(phosphoric acid) or to poly(thiazoline–oxazolines) by treatment with a mixture of poly(phosphoric acid) and a polar solvent.

Polyamides containing pendant hydroxyl groups and their derived polyoxazolines

AbstractBisaminoalcohols were prepared from bisepoxides and ammonia. They were subjected to a polycondensation reaction with dicarboxylic acid chlorides to form polyamides containing hydroxyl groups. These polymers had an inherent viscosity in the range of 0.36 to 1.45 and gave tough, transparent films by solution casting. Polyoxazolines were obtained by treating these polyamides with thionyl chloride.

Relation of Structure to Properties in Polyurethanes. Crosslinking Studies

Abstract The present work was undertaken to assess the effect of crosslink structure on the properties of the elastic network derived from a linear polyetherurethane elastomer. In order to study this effect, a polyetherurethane was synthesized which contained two types of reactive sites suitable for establishing crosslinks— pendant hydroxyl groups for reaction with diisocyanate curatives and pendant double bonds for vulcanization with sulfur. Incorporation of both types of curing sites within the same linear polymer served to hold constant variables which might otherwise influence vulcanizate properties. Thus, the elastic networks formed by both curing systems were produced from the same polymer, and such factors as polymer molecular weight and molecular weight distribution, interchain forces and cure site distribution remained constant. Furthermore, the curing sites have been placed on pendant groups, well removed from the main polymer chain, in order to avoid degradation of the polymer by side reactions which may accompany sulfur vulcanization. It is recognized that common elastomers with internal unsaturation, such as SBR and natural rubber, can be crosslinked by more than one method (e.g., with sulfur, peroxides, or high energy radiation), but the extent and nature of side reactions which may occur is not known with certainty. There are possibilities of polymer degradation reactions with all of these curing systems, and the occurrence of such degradation reactions would cloud any conclusions concerning the relation between crosslink structure and vulcanizate properties.

Relation of structure to properties in polyurethanes

AbstractA polyurethane bearing pendant hydroxyl groups and carbon‐carbon double bonds was prepared. Curing was carried out by diisocyanates of different lengths and by an accelerated sulfur recipe. The vulcanizate properties of modulus, hardness, and resilience were found to be independent of both the length and chemical nature of the crosslink. Compression set, however, was always higher for the sulfur cures, an effect which can be attributed to the disulfide structure of this particular crosslink. Both physical and chemical evidence support this structure. Diisocyanate curing of the dolyurethane via the hydroxyl groups is a clean‐cut, essentially quantitative reaction which provided an absolute method for determining the degree of crosslinking. Excellent agreement was obtained between the physical degree of crosslinking as determined by equilibrium modulus and the chemical degree of crosslinking. This agreement provides further verification of the network‐statistical theory of rubber elasticity in highly swollen systems. No chain entanglement was observed.