Resistance swelling

Water-swell resistance Fair Excellent Excellent Excellent Fair to Excellent Excellent Excellent Excellent... 

Both dynamic permanent set and oil swell resistance are improved on addition of Perkalink 900, indicative of the greater thermal and mechanochemical strength of the cross-links formed from Perkalink 900 compared to sulfidic cross-links. Data are shown in Figures 14.25 and 14.26. 

PVC/NBR polymer blends can be produced as colloidal or mechanical blends, the former generally giving superior properties. Commercially available blends have PVC contents ranging from 30-55%. The blends have reduced elasticity, which gives improved extrudability, but they also exhibit superior ozone resistance, improved oil swell resistance, and tensile and tear strength this, however, is achieved at the expense of low temperature flexibility and compression set. The ozone resistance of such blends is, however, only improved if the PVC is adequately distributed and fluxed. This is harder to achieve in mechanical blends, but if it is not achieved failure due to ozone attack can occur. 

Zeolite/polymer mixed-matrix membranes prepared from crosslinked polymers and surface-modified zeolite particles offered both outstanding separation properties and swelling resistance for some gas and vapor separations such as purification of natural gas. Hillock and coworkers reported that crosslinked mixed-matrix membranes prepared from modified SSZ-13 zeolite and 1,3-propane diol crosslinked polyimide (6FDA-DAM-DABA) synthesized from 2,2 -feis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, p-dimethylaminobenzylamine-and 3,5-diaminobenzoic acid displayed high CO2/CH4 selectivities of up to 47 Barrer and CO2 permeabilities of up to 89 Barrer under mixed gas testing conditions [71]. Additionally, these crosslinked mixed-matrix membranes were resistant to CO2 plasticization up to 450 psia (3100kPa). 

From this result on MRS, we expected that a combination of phenolic-resin-based resist and aqueous alkaline developer would lead to etching-type dissolution and non-swelling resist patterns. In this paper, we report on a new non-swelling negative electron beam resist consisting of an epoxy novolac, azide compound and phenolic resin matrix (EAP) and discuss the radiation chemistry of this resist. 

Vacuum Curing Effect. In the early stage of this work, we investigated a mixture of epoxy novolac and poly(p-vinyl phenol) (EP) to obtain an electron beam sensitive non-swelling resist. Epoxy novolac was chosen as the sensitizing component, because epoxy groups are known to be electron-beam-sensitive substituents (2). However, it is also known that electron beam resists... 

Improvement of the mechanical properties of elastomers is usually reached by their reinforcement with fillers. Traditionally, carbon black, silica, metal oxides, some salts and rigid polymers are used. The elastic modulus, tensile strength, and swelling resistence are well increased by such reinforcement. A new approach is based on block copolymerization yielding thermoelastoplastics, i.e. block copolymers with soft (rubbery) and hard (plastic) blocks. The mutual feature of filled rubbers and the thermoelastoplastics is their heterogeneous structure u0). 

Swelling-resistance. Water-absorbing and swelling directly distorts the materials shape and size and reduces their mechanical performance. 

Swelling resistance of fluoroelastomers is directly related to the fluorine content in the molecule. This is demonstrated by data in Table 5.3 [9]. For example, when the fluorine content is increased by mere 6% (from 65% to 71%), the volume swelling in benzene drops from 20% to 3%. Copolymers of VDF and HFP have excellent resistance to oils, fuels, and aliphatic and aromatic hydrocarbons, but they exhibit a relatively high swelling in low-molecular-weight esters, ketones, and amines, which is due to the presence of the VDF in their structure [10]. VDF-based fluoroelastomers... 

In order to enhance the overall performance of the membrane, it is necessary to modify the membrane material or the structure (41). The objectives for modification of the existing membranes are to increase flux, selectivity, and chemical resistance (solvent resistance, swelling resistance, and fouling resistance). Some of the most commonly practiced membrane modification methods are listed in Table 3. 

A synthetic rubber that has considerably better heat resistance than NBR, some reduced swelling resistance, and more resistance to chemicals and ozone. It is cross-hnked by the peroxide process. 

EGDMA, ALMA, etc. Intraparticle crosslinking for solubility control, reduction of thermoplastic flow, solvent swelling resistance. 

Widjojoa N, Chnnga TS. 2009. Pervaporation dehydration of C2-C4 alcohols by 6FDA-ODA-NDA/Ultem dnal-layer hollow fiber membranes with enhanced separation performance and swelling resistance. Chem. Eng. J. 155 736-743. 

The mechanical properties of the membrane are equally important, although in the scientific literature this aspect is largely imderrepresented. hi addition to tensile strength and elongation at break values, dimensional stability upon swelling, resistance to crack formation, and propagation also have to be considered. Creep of the polymer is likely to occur because the... 

Elastomer reinforcement means different things to different people. Increases in modulus, tensile strength, and swelling resistance are all measures of reinforcement, but abrasion resistance is the most important index, especially to tire manufacturers. Unfortunately, abrasion resistance is a most difficult quantity to measure meaningfully. 

Difunctional dichlorosilanes are used as raw materials for the synthesis of silicone rubbers (see Fig. 2). The outstanding raw material in terms of quantities is dichlorodimethylsilane [2]. Dichloromethylvinylsilane and, especially for crosslinking agents, dichloromethylsilane are used in smaller quantities. High-transparency speciality polymers with glass transition temperatures below -100°C are produced from dichloromethylphenyl- or dichloro-diphenylsilane as copolymers. Dichlorotrifluoropropylmethylsilane is the educt for particularly swell-resistant polymers. 

There are other potential developments in the future for all the positive silicone properties. Certainly there is still a need for development in tensile strength, swelling resistance in oil and abrasion resistance. Price is rapidly becoming a major factor in all applications, and there is no... 

Also called Thioplasts or Thiokol. These are special purpose rubbers. General properties include poor mechanical properties excellent resistance to oils and degreasing solvents. The swelling resistance increases as the sulphur content increases. Good oxidative, ozone, and weathering resistance. Approximate working temperature range -50 C to + 90 C. 

The brittleness temperatures of polyurethane rubber vulcanizates generally range between -22 and -35°C. The vulcanizates swell very little in aliphatic solvents and motor fuels. Their swelling resistance to polar liquids (e.g., chlorinated hydrocarbon, esters, and ketones), however, is not as good. The harder grades generally exhibit the better resistance to swelling. 

Cotton Medium Low Unstable Low resistance, swelling Resistant Resistant Retistant Resistant... 

Low-Pressure Good Good Resistant Resistant Swelling Resistant Resistant Reastant... 

Radiation Change of properties - chemical decomposition - strength change - ductility change - colour change - swelling - resistivity change - bumup... 

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