Swelling behavior of porous copolymers based on alkyl methacrylate esters

2004

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ABSTRACT:Hydrophobic, but water-wettable porous resins based on divinylbenzene (DVB) and methyl acrylate (MA) were prepared with a wide range of pore structures by suspension copolymerization under different conditions. By using purified DVB (98.8%), the specific surface area for the resulting MA/DVB resins could reach high values at high DVB levels, while these resins are wettable by direct contact with water. An increased content of MA significantly increases the porosity of the resins, whereas the solvating power of the porogen affects both pore structure and waterwettability of the MA/DVB resins profoundly. Treating these MA/DVB resins with ferric chloride in the presence of dichloroethane gives products with larger surface areas and an enhanced water-wettability.

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Pore structure of water‐wettable hydrophobic resins based on divinylbenzene and methyl acrylate

Jia

Zhao

2004

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“…The apparent density ( d a , g/mL) and true density ( d t , g/mL) of the resins were measured according to the methods previously described,6 from which the pore volume V p (mL/g) was calculated using the equation The water uptake ( V w , mL/g) was measured by using a centrifuge method, with a relative error of 3% or less for samples where the value of water uptake is above 0.3 mL/g 6, 7. Except for the dynamic swelling experiments, the water uptake was always measured after the swelling equilibrium had been achieved, by direct contact of the resin with water (direct swelling), it usually took about 2 days at room temperature, but for some samples the equilibrium time extended to 2 weeks or more depending on the resin compositions.…”

Section: Methodsmentioning

confidence: 99%

Water‐swellable hydrophobic porous copolymer resins based on divinylbenzene and acrylonitrile. I. Water‐swelling behavior

Tang

Wei

2004

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Hydrophobic porous copolymer resins based on divinylbenzene (DVB) and acrylonitrile (AN) could be prepared as directly swellable in water by using purified DVB (98.8%) and technical DVB (79.3%) in the presence of 1,2-dichloroethane as porogen. Compared with the resins based on DVB and methyl acrylate (MA/DVB resins), the AN/DVB resins thus obtained are waterswellable over a wider range of copolymer compositions, and the swelling ability of the AN/DVB resins in water was further confirmed by investigating the water-swelling behavior of the AN/DVB resins undergoing solvent treatment. The copolymer composition (AN and DVB contents) of the resins and the property of the porogen affect the waterswellable behavior of the AN/DVB resins profoundly. The results in this paper provide additional evidence to support the hypothesis that the swelling ability of a hydrophobic porous copolymer in water originates from the existence of the inner stresses in the strained polymer network of the resins and the weak interaction between polymer and water that is negligible in the case of a conventional hydrophobic polymer.

“…Copolymer resins were prepared by the usual suspension polymerization in the presence of toluene or its mixture with n ‐heptane as porogen 6, 7. The monomers were first mixed well with the porogen to form an organic phase in which the initiator, 2,2′‐azobis(isobutyronitrile), was added in the amount of 1 wt % of monomers.…”

Section: Methodsmentioning

confidence: 99%

Water‐swelling behavior of hydrophobic porous copolymer resins composed of two kinds of crosslinkers

Zhao

Wang

2004

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ABSTRACT:Hydrophobic, but water-swellable, porous copolymer resins composed of divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDM) or ethylene glycol diacrylate (EGDA) were prepared by using purified DVB (98.8%) in the presence of toluene as porogen. The EGDM/ DVB resins thus obtained, whose polarity was nearly identical to that of the resins based on DVB and methyl methacrylate (MMA) at the same DVB levels, were water-swellable by direct contact with water up to a DVB content of 64%, whereas the latter did not swell in water at any DVB levels. EGDA is also hydrophobic, but with a polarity greater than that of EGDM. As a result, the EGDA/DVB resins were more water swellable than EGDM/DVB resins, and could also be prepared as water-swellable materials by using technical DVB (79.3%), besides the use of the purified DVB. All these results were explained on the basis of the network rigidity (crosslinking density) and the polymer polarity of the resins that were formed in the presence of a well-solvating porogenic solvent.