磺化乙丙橡胶离聚体的熔融流动性及力学性能

研究了不同因素包括相转移催化剂、磺化度、中和度、中和用阳离子及增塑剂等对磺化乙丙橡胶离聚体的熔融流动性及力学性能的影响。结果表明,在合适条件下可得到Ｂｒａｂｅｎｄｅｒ扭矩为３５～４０Ｎｍ、拉伸强度为２０～２８ＭＰａ、断裂伸长率为５００％～６００％、永久变形小于１０％的热塑性弹性体     

Dynamic mechanical and melt rheological properties of sulfonated poly(butylene succinate) ionomers

A series of poly(butylene succinate) ionomers (PBSi) containing 5-sodium sulfoisophthalate units were prepared by bulk polymerization of succinic acid and 1,4-butanediol in the presence of dimethyl 5-sulfoisophthalate sodium salt (DMSI) up to 5 mol% of diacid monomer. Conspicuous variation of the storage modulus for PBSi was observed, depending on the content of DMSI. The increasing rate of cluster T_g was lower compared to those of amorphous polymer-based ionomers. These results were probably due to the lower clustering ability of semi-crystalline PBSi as compared with amorphous-based ionomers. Non-contact atomic force microscopy confirmed that the size of PBSi-3 clusters was about 40∼50 nm, demonstrating that the clusters were aggregated. Melt rheological analysis was carried out to investigate the effects of ionic groups on the rheological properties as a function of temperature or shear force in the molten state. The melt viscosities of PBSi showed higher values than the parent PBS up to about 190 °C, while with further increasing temperature a falling inflection region of melt viscosity was observed. It was suggested that the relaxation of PBSi chains was due to the thermal dissociation of ionic aggregates.     

Melt flow and mechanical properties of sulfonated butyl rubber ionomers

Study of melt flow properties and mechanical properties of sulfonated butyl rubber ionomers showed that in the case of lithium ionomers addition of zinc stearate lowered obviously the melt viscosity, represented by torque value of a Brabender rheometer, and enhanced tensile strength of the ionomer up to 25% of zinc stearate, while in the case of ethylamine neutralized ionomer addition of zinc stearate lowered the melt viscosity not so obviously as in the case of lithium ionomer and slightly affected the tensile strength. Amine neutralized ionomers exhibited very low permanent sets, while the lithium ionomer showed much higher permanent set, which increased with sulfonate group and amount of zinc stearate added. Increase of neutralization degree below equivalent ratio of 1 significantly raised the melt viscosity and tensile strength. For monovalent cation ionomer, melt viscosity and tensile strength diminished with decreasing ionic potentials, but for divalent cation ionomers with increasing ionic potentials and with decreasing covalent character tensile strength decreased and melt viscosity increased. For different amine neutralized ionomers tensile strength decreased in the following orders: ethylamine > triethylamine > diethylamine; isopropylamine > ethylamine > tertiary butylamine > methylamine; ethylamine > hexylamine > dodecylamine > octadecylamine.     

Dynamic mechanical properties and morphology of sulfonated polystyrene ionomers neutralized with mixtures of various cations

Summary The effects of the addition of mixed cations to the acid form sulfonated styrene copolymers on their mechanical properties and morphology were investigated. It was found that the matrix T _g, does not Change with the type of cations. However, the Cluster T _g, ionic moduli, and the Position of the SAXS peak were affected by the type of cations. The decreasing trends of Cluster T _g with increasing the amount of cesium and zinc cations in Na/Cs, Bai Cs, and Ba/Zn mixtures, were explained on the basis of the considerations of the size, Charge, and type of cations, which alter the degree of clustering as weil as ion-hopping mechanism. Received: 7 October 2002/Revised Version: 13 December 2002/ Accepted: 14 December 2002 Correspondence to Joon-Seop Kim     

Characterization of blends of an amorphous polyamide with lightly sulfonated polystyrene ionomers

Improved compatibility of blends of polystyrene and an amorphous polyamide was achieved by lightly sulfonating the polystyrene. Hydrogen bonding between amide groups and either sulfonic acid or metal sulfonate groups lowered the interfacial tension between the two polymers, which led to a much finer dispersed phase size in blends involving the sulfonated polystyrene. At relatively high sulfonate to amide ratios, the two polymers formed a miscible blend. Improved mixing of the phases was verified by shifts in the glass transitions, and the specific interactions that occurred were characterized by Fourier transform infrared spectroscopy.     

Synthesis and physical properties of sulfonated syndiotactic polystyrene ionomers

Sulfonation of highly stereoregular syndiotactic polystyrene has been accomplished in 1,1,2‐trichloroethane and chloroform (60/40 v/v) mixed solvent. FTIR spectroscopy was used to confirm that the sulfonated syndiotactic polystyrene was the product of the sulfonation reactions. Sodium, potassium, zinc (II), manganese (II) and cobalt (II) salts of the sulfonated polymers exhibited behaviour indicative of strong interactions. FTIR spectroscopy and DSC data showed that the roles of the cation–anionic site interactions in alkali form and transition metal form ionomers are somewhat different. The DSC data also showed that the alkali metal cations had more pronounced effect on T_g than did the transition metal cations. In addition, the crystallization behaviour of the ionomers with a low degree of sulfonation also exhibited considerable differences in comparison with the neat syndiotactic polystyrene. The melting points (T_m) and the degree of crystallization (X_c) were significantly lowered by the presence of the sulfonic acid groups or the sulfonate metal groups. Moreover, the ionomers were more thermally stable and more hygroscopic than the unmodified polymer. © 2001 Society of Chemical Industry     

Effects of the cation valence on the mechanical properties of sulfonated polystyrene ionomers containing dicarboxylate salts

The dynamic mechanical properties of Ba(II)-neutralized poly(styrene-co-styrene sulfonate) ionomers-containing Ba salt of aliphatic diacid were investigated and compared with those of Na(I)-neutralized ionomers-containing Na diacid salt. It was found that the addition of diacid salts led to a negligible change in the matrix and cluster T _gs of the Ba and Na ionomers regardless of the chain length of the aliphatic diacid salts. The log E′ of Ba ionomers, however, increased linearly with increasing chain length of Ba diacid salt, which was different from that of Na ionomers. On increasing wt% of the salts in the ionomers, the matrix T _gs of Ba and Na ionomers did not change, but the cluster T _gs increased slightly for Ba and Na ionomers, except for the Na ionomer-containing C₁₆ diacid salt. In addition, the log E′ increased linearly with the wt% of diacid salts, but the increasing rate was higher for the Ba ionomers, compared to Na ionomers. Thus, it was suggested that the Ba diacid salts would face more difficulty in the formation of multiplet with the ionic groups of the ionomers, compared to Na ionomer system; thus, more Ba diacid salts were phase-separated, which showed a stronger filler effect. In addition, since the Ba ionomers did not flow easily above the cluster T _g of the ionomers, it was proposed that the multiplets of Ba ionomers acted still as effective physical cross-links above cluster T _g, to some extent. Finally, it was concluded that the difference in anionic groups, the increasing amount of Ba salts, and the divalent cation enhanced the filler effects strongly.     

Dynamic mechanical properties of weakly clustered poly(styrene-co-sodium citraconate) ionomers

Summary The properties of poly(styrene-co-citraconate) ionomers were investigated dynamic mechanically. It was found that the loss tangent peak for the matrix glass transition decreased with increasing content of ionic units, while the loss tangent peak for the cluster glass transition was barely detectable. However, the ionic modulus values of the citraconate ionomers as a function of the amount of ionic units were comparable to those of well-clustered methacrylate ionomers. Thus, it was postulated that the ionic modulus was affected by both clustering due to the overlapping of regions of restricted mobility and strong physical cross-links originated from the ionic association of ca. 4 ion pairs. Received: 16 March 2001/Revised version: 25 April 2001/Accepted: 27 April 2001     

磺化三元乙丙橡胶离聚物的合成

用浓硫酸和醋酸酐为三元乙丙橡胶（EPDM）反应制备了磺化三元乙丙橡胶离聚物（S－EPDM）。探讨了浓硫酸用量、EPDM胶液浓度、磺化浓度、反应时间对磺化的影响以及磺化三元乙丙橡胶锌离聚物（S－EPDM－Zn)的应用。     

Investigation of phase morphology,thermal behavior,and impact properties of polyamide-1010/polystyrene blends compatibilized by lightly sulfonated polystyrene ionomers

The phase morphology, thermal behavior, and impact properties of polyamide-1010 (PA)/polystyrene (PS) blends compatibilized by sulfonated polystyrene (HSPS) and their zinc salts (ZnSPS) were investigated, using a dynamic mechanical analyzer (DMA), a scanning electron microscope (SEM), a differential scanning calorimetry (DSC), and a pendulum impact tester. It was found that the addition of the ionomer had an improved effect on the phase morphology of the resulting blends, where the HSPS was a more effective compatibilizer than was the ZnSPS due to its low melt viscosity and less self-agglomeration in the PA matrix. DSC results showed that with increasing the ionomer content the amount of the less perfect crystals of PA increased in these blends and, hence, led to a small increase in the crystallinity of the PA phase. The crystallization rate of the PA in the resulting blends was accelerated slightly by the ZnSPS but was decreased by the HSPS, which was probably due to the nucleation effect of ZnSPS for PA but no nucleation of HSPS. The best improvement in the notched impact strength of the blends was achieved with the content of the ionomer up to 20 wt % based on the amount of PS. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 61–69, 1998     

Self-organization of sulfonated polystyrene ionomers in low-polarity solvents

The self-organization of ionomers based on sulfonated polystyrene containing sodium sulfonate groups SO₃Na in chloroform, deuterated toluene, and deuterated benzene is studied by the method of small-angle cold neutron scattering. It is shown that in chloroform, at a content of ionogenic groups of 1.35 mol %, chains undergo coil-to-globule conformation transformations owing to their electrostatic interactions. An increase in the amount of SO₃Na groups to 2.6 mol % leads to the assembly of ionomer chains into a hollow spherical structure with the solvent inside it (vesicle). Ionomer chains in chloroform join and form stable pairs. The structural organization of ionomers containing different amounts of SO₃Na groups (0.5–5.8 mol %) in deuterated toluene manifests itself as the formation of effective chains comprising up to seven macromolecules and functioning as the main structural elements of the system. Chains preserve the conformation of the Gaussian coil even at a degree of sulfonation of 5.8 mol %, when the distance between ionogenic groups along the chain is comparable with the length of the Kuhn segment. The effective chains of ionomers with a high content of ionogenic groups are characterized by sizes smaller than PS coils; they are composed of one to two macromolecules, and their density is increased. The self-organization of such species in deuterated toluene facilitates formation of secondary structures, namely, clusters consisting of four to five effective chains. In deuterated benzene, ionomer chains form supramolecular structures (associates) that behave as Gaussian chains and include 13–18 macromolecules at moderate and high degrees of sulfonation of PS. When the centers of gravity approach each other at a distance of the diameter (40–70 nm), associates come into contact and give rise to clusters. It is found that, at the scale of segments within the chain segment, the rigidity of chains is increased due to formation of intermolecular physical crosslinks between chains arising from electrostatic dipolar interactions of ionogenic groups.     

磺化丁基橡胶离聚体与其他聚合物的共混

研究了磺化丁基橡胶(IIR)离聚体与苯乙烯-丁二烯嵌段共聚物、聚丙烯、高密度聚乙烯、氯醚橡胶及顺丁橡胶的共混。结果表明,磺化IIR离聚体与苯乙烯-丁二烯嵌段共聚物或聚丙烯的共混物在拉伸强度方面呈现协同效应,随着磺化IIR离聚体质量分数的增加,聚丙烯的熔点下降。磺化IIR离聚体与高密度聚乙烯的共混物在拉伸强度方面呈现加和效应,而其与氯醚橡胶或顺丁橡胶的共混物在拉伸强度方面则呈现抵销效应。     

Sulphonated polyisobutylene telechelic ionomers: 12. Solid-state mechanical properties

The solid-state mechanical properties of well defined sulphonated polyisobutylene telechelic ionomers are presented. Specifically, the effect of (1) molecular architecture, (2) molecular weight, (3) type of cation used for neutralization and (4) excess neutralizing agent has been investigated. In addition, the effect of moisture and ionic plasticizer on the stress-strain behaviour has also been studied.

These ionomers do not display the characteristic small-angle X-ray scattering (SAXS) peak, which is indicative of the presence of clusters, above a number-average molecular weight of about 10 000. However, below this molecular weight a weak shoulder is sometimes observed on the SAXS curve. The tri-arm species form a network structure at ambient temperatures which results in materials with good mechanical properties. The mechanical properties of the linear difunctional species are inferior to those of the three-arm star trifunctional species due to a less well developed network structure. The monofunctional species are very tacky at ambient temperatures and cannot be handled as solid materials. However, by their incorporation into the trifunctional systems they do serve as a model for ‘dangling ends’. As expected, these blends display significantly different properties than those possessed with the pure trifunctional species.

Addition of excess neutralizing agent significantly increases the high deformation properties with little effect on Young's modulus. A simple morphological model has been postulated in which it is suggested that the excess neutralizing agent resides at the ionic sites rather than being uniformly distributed throughout the matrix. Zinc-neutralized ionomers show stress-strain behaviour which is comparable to the potassium- and calcium-neutralized materials at ambient conditions, but the softening temperature is lower for the zinc neutralized material. Water absorption in these materials is relatively low. Addition of zinc stearate, an ionic plasticizer, facilitates melt processing by lowering the viscosity at high temperatures yet at ambient temperatures it crystallizes and acts as a reinforcing filler thus increasing Young's modulus.     

Gas diffusion electrodes containing sulfonated polyether ionomers for PEFCs

Gas diffusion electrodes (GDEs) containing sulfonated polyether (SPE) ionomers as proton conducting binder have been prepared and evaluated in H₂/O₂ polymer electrolyte fuel cells. An autoclave treatment has been applied for the first time to a hydrocarbon ionomer for the preparation of GDEs. The GDEs worked well as anode without practical overpotential up to 800 mA/cm² of the current density. As cathode, the GDEs showed significant dependence on the SPE content and its ion exchange capacity (IEC). Higher catalyst utilization was achieved for the GDEs with higher SPE content due to enhanced proton conduction. Cyclic voltammetry implied higher catalyst utilization of the SPE-based GDEs than that of the conventional Nafion^®-based GDEs. Scanning transmission electron microscopy (STEM) revealed that the SPE ionomer coated uniformly on the surface of Pt/carbon black catalysts. Humidification conditions affect proton conductivity and swelling of the SPE ionomer and thus were crucial for the cathode performance. SPE ionomer with medium IEC (2.17 meq/g) served best in GDEs in terms of catalyst utilization.     

Dynamic mechanial properties of sulfonated cyclized cis-1,4-polyisoprene

Acetyl sulfate was used as sulfonating agent for the sulfonation of cis-1,4-polyisoprene. IR and NMR spectra showed that the sulfonation was accompanied by extensive cyclization. A series of DSC and loss tangent studies of both the sodium salts and the methyl esters was undertaken. It was found that cyclization exerts a profound influence on the micrbrownian segmental motion of the hydrocarbon matrix and is the dominant factor in raising the glass transition temperatures. However, the differences in the mechanical properties between salts and esters suggest that the presence of ions does influence the melt viscosities and shear moduli of the sulfonated cyclized rubbers; this influence can be minimized by esterification or water absorption. It is seen that the ionic effects in these materials are quite typical of those encountered in a wide range of other ionomers.     

Morphology and mechanical properties of styrene homoblends of methacrylate and sulfonate ionomers

Summary Dynamic mechanical properties and morphology of homoblends of sulfonated polystyrene and poly(styrene-co-methacrylate) ionomers were investigated. While two tan δ peaks were found in the unblended ionomer samples, three tan δ peaks were observed for the homoblend. The peak at 152 °C is thought to be due to the matrix T _g, and those at 194 and 261 °C probably represent the glass transitions of cluster regions, containing methacrylate-rich multiplets and sulfonate-rich multiplets, respectively. In SAXS profile, only a very broad plateau-type feature was seen for the homoblend. This result implies either that the number density of the scattering centers at prevalent distances is low or that each scattering center has a different electron density. Thus we suggest that in the present study the multiplets of the homoblend consist of random mixtures of sulfonate and carboxylate groups. Received: 27 July 1998/Revised version: 21 September 1998/Accepted: 19 October 1998     

磺化SBS离聚体与结晶聚烯烃的共混物

研究了磺化SBS离聚体与聚丙烯或高密度聚乙烯在质量分数为10％的硬脂酸锌存在下熔融共混得到的共混物的力学性能。结果表明,共混物的拉伸强度均呈协同效应,这是因为生成了热塑性互穿网络结构。随着聚烯烃含量的增加,共混物由热塑性橡胶变成增韧树脂。     

Isothermal crystallization of lightly sulfonated syndiotactic polystyrene/montmorillonite clay nanocomposites

Lightly sulfonated syndiotactic polystyrene (sPS) nanocomposites were prepared using a solution intercalation technique, and the effect of montmorillonite clay on the crystallization kinetics of sulfonated sPS ionomer nanocomposites was systematically studied. Wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) were used to evaluate the dispersion of clay platelets within sPS and sulfonated sPS ionomer (SsPS) matrices. Experimental results obtained from WAXD and TEM revealed a predominately exfoliated morphology within the SsPS ionomer containing 5 wt.% of organically-modified clay. The corresponding non-sulfonated sPS control exhibited a mixed morphological structure consisting of intercalated platelets and many platelets that were present as micron-sized agglomerates. Using differential scanning calorimetry (DSC), the Avrami approach was used to elucidate information related to nucleation and growth within the sPS and SsPS systems during the isothermal crystallization process. Pristine and organically-modified clays significantly increased the overall crystallization rate of the SsPS ionomer, while the nanoclays slightly decreased the crystallization rate of the non-ionic sPS. The mechanistic origins of increased crystallization rates within the SsPS ionomer clay nanocomposites were attributed to multiple phenomena including disruption of the ionomer electrostatic network and a nucleating effect due to the presence of well-separated, homogeneously dispersed clay platelets.     

Dynamic mechanical properties of polymers

A technique, employing samples in the form of tuning forks, to measure the mechanical properties of polymers is presented. Results for low density polyethylene, polypropylene, and polycarbonates are shown. A large transition is observed for polypropylene at approximately +10°C and a small transition at ?100°C for the polycarbonates. Polycarbonate data has also been obtained from 20 to 150°C, at approximately 70 cps. Effects of time, temperature, and history are presented.