Some electron microscopic observations of sulphonated EPDM polymers

The electron microscopy observations have been conducted with films cast from dilute solution based on sulpho EPDMs derived from various cations. Some very interesting morphological features are observed. Aggregated regions of sizes in the range of 500 to 1000 nm are found in the metal sulphonated polymers, while the absence of structure is observed in the base polymer and its acid derivative. This type of morphology has not been previously reported, and these aggregates appear about 100 times larger than typically expected for phase separated ionomers. Possible explanations of these morphologies are discussed.     

Behaviour of sulphonated EPDM in multicomponent/multiphase systems

The interactions of polymers containing low levels of ionic groups in selected environments has been a relatively unexplored area. For selected applications, it is important to understand how these polymers interact with a variety of cosolvents and/or solid substrates. The purpose of this study is aimed towards gaining an insight into these interactions. The solution behaviour of various inorganic salts (calcium, magnesium and zinc) of sulphonated ethylene-propylene diene monomers (EPDM) was investigated in order to determine the relative strength of interactions between sulphonate groups, cosolvents of varying structure and substrates possessing a specific chemistry. Viscosity-time-temperature relationships show that the properties of the polymer-cosolvent solutions are controlled to a large extent by ionic forces. The magnitude of these forces is dependent upon the nature of the cation and the specific molecular structure of the cosolvent. The weakest interaction was found to occur between the calcium neutralized polymer and cosolvent, while magnesium and zinc neutralized samples showed progressively stronger interactions. The extent to which these ionic forces can interact with their ‘environment’ depends upon the molecular structure of the cosolvent, in particular the structure of the polar ‘head’ is of paramount importance. These become even more apparent when the polymer and polymer-cosolvent complex is permitted to adsorb onto insoluble, solid substrates possessing a specific surface chemistry (in this instance, metal sulphate substrates). The results show that if the cation on the sulphonated polymer is identical to the cation contained in the metal sulphate, the adsorption of polymer is maximized (i.e., like prefers like). In addition, the nature of the cation is very important in determining the extent and, most probably, the mechanism of adsorption.     

Infra-red dichroism investigation of molecular viscoelasticity using isotopically labelled block copolymers

Summary Infra-red dichroism has been used to measure the orientation of the different sequences of isotopically labelled block copolymers. We have determined the orientation from dichroic ratios of two bands of deuterated polystyrene, and compared in block copolymers the orientation of the central part of the chain with that of the ends. The relaxation of the ends is more rapid, than that of the center, which exhibits a plateau.     

Infra-red and Raman spectra of poly(m-methylene terephthalate) polymers

A detailed comparison of the infra-red and Raman spectra of poly(trimethylene terephthalate) (3GT), poly(tetramethylene terephthalate) (4GT) and poly(ethylene terephthalate) (2GT) is reported. Particular attention has been given to the changes in the spectra which occur on crystallization. Additionally, the spectra of oriented 4GT samples have been examined under applied stress, because this produces a change in the structure of the crystalline regions. It is shown that the differences between the spectra of these polymers can be satisfacorily accounted for by changes in the conformation of the molecular chains involving both trans/gauche isomerism in the glycol sequence and the planarity of the terephthalate residue.     

Effect of zinc stearate on properties of melt processable ionomer based on sodium salt of sulphonated maleated EPDM rubber

Abstract

Sulphonation of maleated copoly (ethylen/propylen/diene), followed by its neutralisation by sodium hydroxide produces an ionomer containing both carboxylate and sulphonate anions on the backbone. Addition of zinc stearate lowers the melt viscosity of the ionomer, which is higher than the corresponding non-ionomer. Dynamic mechanical thermal analysis shows that zinc stearate acts as a low reinforcing filler under ambient conditions and as a plasticiser above 100°C (i.e. above the melting point of zinc stearate). For example, incorporation of zinc stearate causes an increase in storage modulus E′ at 25°C, but a sharp decrease in E′ at 110°C. Furthermore, the plot of tan δ v. temperature reveals that tan δ at the low glass–rubber transition temperature T _g decreases, while tan δ at the high temperature ionic relaxation temperature T _i increases in the presence of zinc stearate. Incorporation of carbon black lowers tan δat T _g and increases tan δ at T _i, thus strengthening the biphasic structure of the ionomer. The ionomer shows higher tensile strength and modulus than the corresponding non-ionomer. Addition of zinc stearate increases the tensile strength and elongation at break, with marginal decrease in modulus. Carbon black increases the stress–strain properties of the zinc stearate filled ionomer. Reprocessability studies of the ionomer filled with zinc stearate and carbon black show that the material can be recycled without a decrease in properties.     

Heterogeneous reactions of polymers: 4. Melting behaviour of heterogeneously chlorinated and sulphonated polyethylenes

The melting behaviour of heterogeneously chlorinated and sulphonated high-density polyethylene was studied by differential scanning calorimetry. It was found that an increase in T_m takes place at high degrees of substitution in the amorphous phase. For sulphonated polyethylenes the increase in T_m was also dependent on the type of the counterion. The effect is interpreted as a decrease in configurational entropy upon fusion due to the restraints that the highly chlorinated and sulphonated amorphous regions impose on the adjacent crystallites.     

Dielectric properties of sulphonated polystyrene

Polystyrene was sulphonated with chlorosulphonic acid and the dielectric properties of the films were measured as a function of degree of sulphonation and water content at 27°C at frequencies of 10³ to 10⁶ Hz. The sulphonated samples have a high dielectric constant as compared to the unsulphonated polystyrene. The hydration of polystyrene sulphonic acid is a stepwise process.     

Chemical modification of polymers: 17. Dyeing of sulphonated polystyrene films by ion exchange with cationic dyes

Heterogeneous dyeing of free-standing films of surface sulphonated polystyrene by ion exchange with aqueous cationic dyes has been studied. Studies of (1) the optical density of films with a given extent of sulphonation as a function of dyeing times, (2) the optical density for constant dyeing time as a function of extent of sulphonation and (3) the thickness of dye sulphonate layers as a function of both dyeing time and extent of sulphonation have been used to establish times for complete dyeing. Using the thickness measurements, estimates of equivalent volumes of the dye sulphonates were made. Displacement of one dye by another was also studied; used of previously derived analytical techniques for this sort of displacement must be used with care due to differences in degree of aggregation, as demonstrated for methylene blue.     

红外激光光化学

<正> 在经典光化学中,人们常用的是可见和紫外光源,而红外光源是不被人们所重视的,因为红外光子能量比较低,它只能影响分子中振动-转动能级的变化,不足於引起分子中化学键的断裂。但是,红外激光器的发光机理,完全不同於以往任何一种红外光源。红外激光束方向性好、能量高度集中,因而强度高、单色性好,在与物质相互作用过程中,产生前所未有的多光子吸收的现象。近年来,红外激光辐射已用于分离同位索、增强化学反应速率、激光引发的均相热解以及游离基的反应动力学研究等方面,一门崭新的红外激光光化学应运而生了。     

Experimental investigation and modeling of the dissolution of polymers and filled polymers

Dissolution of Polymers is important in various areas, including microlithography, controlled drug and herbicide/fertilizer delivery, and recycling. The dissolution rates of an oxetane polymer in ethyl acetate were obtained and well correlated with a quasi-stationary dissolution model. Equilibrium solubility values obtained from the mathematical model on the basis of the best fit to the dissolution data were found to be in good agreement with equilibrium solubilities obtained in independent experiments. Mass transfer coefficients were also obtained from the mathematical model on the basis of the best fit, and the calculated activation energies were typical for diffusion controlled dissolution. The dissolution of highly filled polymers in various solvents was also investigated using the oxetane polymer filled with ammonium sulfate and aluminum fillers. The dissolution rates for the highly filled polymer were well correlated with a pseudo-homogenous diffusion model.     

Structural investigation of polymers by neutron scattering

Abstract

Neutron scattering is a unique probe of the structural and dynamic properties of polymeric materials. Two properties of the neutron particle have played a major role in the development of the technique: (i) length and timescales accessed by neutron scattering simultaneously match those of typical molecular processes, and (ii) the capability to manipulate the contrast by deuteration. Starting from what could now be regarded as rather simple experiments on common polymeric systems, the technique has been developed into a tool used to elucidate structure and dynamics of increasingly complex, multi-component materials. Exploiting the high penetration power of the neutron particle, in situ measurements can be performed, so that structural changes can be followed mimicking processing conditions. With continuous improvements in neutron flux and instrumentation, the range of systems that can be investigated is continuously expanding, as well as the accessible spatial and time range instrumentally accessible. Recent years have seen not only advances in synthetic chemistry, but also in molecular modelling and neutron scattering has afforded a way to compare experimental data and computer simulations. With plans being made for next generation neutron sources, e.g. the second target station at ISIS and SNS in the USA, the future is looking very bright for neutron scattering.     

Syntheses and properties of graft polymers of N‐substituted acrylamides onto EPDM

The graft polymerizations of N‐isopropylacrylamide (NIPAM) or N‐phenylacrylamide (NPAM) onto ethylene‐propylene‐diene terpolymer (EPDM) were carried out with benzoyl peroxide (BPO) as an initiator in toluene or THF. The structures of synthesized graft polymers, EPDM‐g‐N‐isopropylacrylamide (ENIPAM) and EPDM‐g‐N‐phenylacrylamide (ENPAM), were identified by infrared (IR) spectroscopy. The effects of monomer concentration, reaction time, and initiator concentration were investigated on the graft polymerization. The highest graft efficiency of NIPAM was obtained at 0.75 mol/L of NIPAM, 4 g of EPDM, 3 wt % of BPO, and 70°C for 48 h and that of NPAM did not much change up to 0.75 mol/L of NPAM, 4 g of EPDM, 3 wt % of BPO, and 70°C for 72 h. The thermal decomposition temperatures, wettabilities, and tensile strengths of ENIPAM and ENPAM all decreased with an increasing concentration of NIPAM and NPAM moiety in the corresponding polymers, respectively. The morphologies of ENIPAM and ENPAM after irradiation showed many gel particles as compared with those of ENIPAM and ENPAM before irradiation. The UV light and ⁶⁰Co γ‐ray resistances of ENIPAM and ENPAM were worse than those of EPDM due to carbonyl group in NIPAM and NPAM. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3259–3267, 1999     

磺化产品的功能化与绿色化

综述了磺酸盐/硫酸酯盐表面活性剂的国内现状与发展趋势。指出,首先应开发多功能化的磺化产品,以满足未来洗涤用品的发展要求;其次,应开发适合三次采油用的磺酸盐型表面活性剂;再次,应开发适合不同应用领域的油脂基表面活性剂,推进被磺化原料的绿色化进程。     

磺化酚醛吸水树脂的研制

通过引入水化基团—CH2SO3-、控制合成反应工艺、增韧改性等措施,以亚硫酸氢钠、甲醛和苯酚为原料,以ZR-1为增韧改性剂,首次成功研制了磺化酚醛吸水树脂SPA。考察确定了优化反应条件：甲醛与苯酚的摩尔比为1.5～1.8,以无水亚硫酸钠为催化剂,通过磺甲基化法引入磺酸基,磺化度控制在20%,用1%的ZR-1进行增韧改性。制得的SPA为暗红色,具有粘弹性的块状树脂,强度达2 MPa以上,拉伸伸长率为194%,吸水7 h达到饱和,吸水倍数3.2倍。     

Thermal stability of sulphonated styrene-divinylbenzene resins

Sulphonated styrene-divinylbenzene copolymers of different structures were heated in vacuum, a nitrogen stream, water, sulphuric acid and benzene. The stability behaviour was studied by differential thermal analysis at temperatures up to 600°C and by isothermal measurements at temperatures between 150°C and 240°C. In aqueous media decomposition of the resins is determined by hydrolysis of the sulphonic acid groups alone; in vacuum, nitrogen stream and benzene, reactions in the polymer backbone under the influence of sulphuric acid and additional crosslinking due to the formation of sulphones have also to be taken into account.     

磺化酚醛吸水树脂的研制

通过引入水化基团—CH2SO3-、控制合成反应工艺、增韧改性等措施,以亚硫酸氢钠、甲醛和苯酚为原料,以ZR-1为增韧改性剂,首次成功研制了磺化酚醛吸水树脂SPA。考察确定了优化反应条件:甲醛与苯酚的摩尔比为1.5～1.8,以无水亚硫酸钠为催化剂,通过磺甲基化法引入磺酸基,磺化度控制在20%,用1%的ZR-1进行增韧改性。制得的SPA为暗红色,具有粘弹性的块状树脂,强度达2 MPa以上,拉伸伸长率为194%,吸水7 h达到饱和,吸水倍数3.2倍。     

Investigation of new composite materials based on activated EPDM rubber waste particles by liquid polymers

Despite of the variety of existing techniques, there is still a continuous demand in the development of more efficient recycling technologies, for economic and environmental reasons. A new approach for recycling EPDM rubber waste has been recently introduced utilizing a solvent free activation process by addition of liquid polymers (LP). The present study investigates the influence of the content and varying types of activated rubber waste particles (RWP‐LP) in new composites. By varying the proportion of RWP‐LP in the range from 25 up to 75 v/v % information about optimized compositions of new compounds were obtained. It was found that the ratio and type of RWP‐LP induce significant differences in terms of cure characteristics, mechanical properties, crosslink density and morphology. Promising results with high potential application for the production of seal and sealing systems on the industrial scale were obtained by using up to 50 v/v % of RWP‐LP with low ethylene amount. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42097.     

EPDM rubber reclaim from devulcanized EPDM

Two types of ethylene–propylene–diene monomer (EPDM) rubbers, namely an efficient vulcanized (EV) and a semiefficient vulcanized (SEV), have been used to produce devulcanizates in a continuous setup. The devulcanizates are re‐cured using the same recipes as for the virgin rubber. The influence of mixing it with virgin rubber compound, the addition of extra sulfur, the operating devulcanization conditions, and the excess of devulcanizing agent on the mechanical properties (hardness, tensile strength, and compression set) of the reclaim rubbers are studied. Most of the reclaims produced show slightly inferior mechanical properties compared to the virgin rubber. Surface imperfection was observed on the devulcanizate with high devulcanizing agent content. Excellent mechanical properties (all above the standards) of the reclaim were found when the devulcanized profile material was used (EV‐EPDM) to replace the virgin one for application as a roofing sheet material (SEV‐EPDM). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5948–5957, 2006     

Infra-red absorption spectra of ion-exchange resins

Infra-red absorption spectra have been obtained by the KBr disc technique for some fifty commercial ion-exchange resins with quaternary ammonium, tertiary and mixed amine, sulphonic, phosphonic, secondary phosphate, and carboxylic groups, as well as for a number of experimental resins, including some of the solvent-modified type. The use of the technique in structural characterisation of ion-exchange resins is discussed.