Structure and swelling properties of polymer networks synthesized in solution

Two structurally different aromatic dithioesters were synthesized from two dithiols and methacryloyl chloride. The polymer networks based on methyl methacrylate and/or styrene and the new dimethacrylates were subsequently prepared. The polymerization yields of copolymers were in the range of 95–99%. The thermal and mechanical properties of the copolymers were determined by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TG/DTG), and Shore D hardness. The addition of dithioesters—1,5-NAF-S-Met (or 1,4(1,5)-NAF-CH2S-Met) (from 0.5% to 5%) to MMA- or ST-based polymers results in lowering the glass transition temperature (Tg) by about 8 °C. The thioester-containing polymers based on MMA exhibit lower thermal stability than those with ST. The polythioesters are stable up to 250 °C. The UV/vis spectra and refractive indexes of prepared liquid compositions were also measured. The 1,5-NAF-S-Met (and 1,4(1,5)-NAF-CH2S-Met) improved the refractive index values of ST and MMA compositions. The double bond conversion was also determined for all synthesized materials. The swelling studies of polymers with 20% addition of thioester crosslinkers were investigated. For all polymeric materials with 20% addition of thioesters, depolymerization of the network was carried out by thiol-thioester exchange. The depolymerization products were re-reacted in a thiol-ene reaction with 2-hydroxyethyl methacrylate by thermal initiation. The thiol-ene procedure enabled reprocessing of starting polymers and obtaining new materials characterized by distinctly different thermal, mechanical, and swelling properties. The thiol-ene materials exhibit a lower Shore hardness in the range of 20–50 °Sh, as well as decreased Tg values when compared to starting copolymers. Due to these possible exchange reactions, one can facilely manipulate the properties of the polymers which could lead to the manufacturing of the new products with the desired features. Degradation of the cross-linked structure and recycling of copolymers were also discussed.

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Topological Polymer Networks with Sliding Cross-Link Points: The “Sliding Gels”. Relationship between Their Molecular Structure and the Viscoelastic as Well as the Swelling Properties

Macromolecules ◽

10.1021/ma0605043 ◽

2007 ◽

Vol 40 (3) ◽

pp. 535-543 ◽

Cited By ~ 74

Author(s):

Guillaume Fleury ◽

Guy Schlatter ◽

Cyril Brochon ◽

Christophe Travelet ◽

Alain Lapp ◽

...

Keyword(s):

Molecular Structure ◽

Polymer Networks ◽

Cross Link ◽

Swelling Properties

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Semi-interpenetrating Polymer Networks Containing Polysaccharides. I Xanthan/Lignin Networks

High Performance Polymers ◽

10.1177/0954008307081202 ◽

2007 ◽

Vol 19 (5-6) ◽

pp. 603-620 ◽

Cited By ~ 22

Author(s):

Irina Elena Raschip ◽

Cornelia Vasile ◽

Diana Ciolacu ◽

Georgeta Cazacu

Keyword(s):

Xanthan Gum ◽

Polymer Network ◽

Polymer Networks ◽

Temperature Stability ◽

Interpenetrating Polymer Networks ◽

Interpenetrating Polymer Network ◽

Helical Conformation ◽

Swelling Properties ◽

Food Ingredients ◽

Swelling Rate

The polysaccharides are important materials in food, pharmaceutical, cosmetic and related biomedical applications. Xanthan gum is a microbial polysaccharide of great commercial significance. It is well known as one of the best thickening polymers due to its high intrinsic stiffness related to the helical conformation stabilized in the presence of excess salt. It is used in a wide variety of foods for a number of important reasons, including emulsion stabilization, temperature stability, compatibility with food ingredients, and its pseudoplastic rheological properties. Due to its properties in thickening aqueous solutions, as a dispersing agent, and stabilizer of emulsions and suspensions, xanthan gum is used in pharmaceutical formulations, cosmetics, and agricultural products, as well as in textile printing pastes, ceramic glazes, slurry explosive formulations, and rust removers. In this work the crosslinking of a mixture of xanthan and lignins in the presence of the epichlorohydrin, leading to superabsorbant hydrogels with high swelling rate in aqueous mediums, was studied. The swelling properties of these composite hydrogels were investigated. Three different types of lignin have been used namely: aspen wood lignin (L), annual fiber crop lignin (GL) and lignin epoxy-modified resin (LER). Semi-interpenetrating polymer network hydrogels in various ratios were prepared. The influence of gravimetric ratio between components of the semi-interpenetrating polymer networks, as well as the kinetics of water sorption will be discussed. The maximum swelling degree of the hydrogels and the swelling rate constant were determined as a function of the hydrogel's composition. It has been established that the nature of lignin significantly influences swelling process, the chemical modified lignin having a particular behavior.

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Preparation and Swelling Properties of Temperature-Sensitive Semi-Interpenetrating Polymer Networks Composed of Poly[(N-tert-butylacrylamide)-co-acrylamide] and Hydroxypropyl Cellulose

Macromolecular Materials and Engineering ◽

10.1002/mame.200600063 ◽

2006 ◽

Vol 291 (9) ◽

pp. 1044-1051 ◽

Cited By ~ 27

Author(s):

Tuncer Çaykara ◽

Gamze Şengül ◽

Gökçen Birlik

Keyword(s):

Polymer Networks ◽

Hydroxypropyl Cellulose ◽

Interpenetrating Polymer Networks ◽

Temperature Sensitive ◽

Swelling Properties

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Semi-interpenetrating polymer networks based on polyacrylamide and poly[itaconic acid]

Hemijska industrija ◽

10.2298/hemind0311543k ◽

2003 ◽

Vol 57 (11) ◽

pp. 543-546 ◽

Cited By ~ 1

Author(s):

Melina Kalagasidis-Krusic ◽

Biljana Nikolic ◽

Jovanka Filipovic

Keyword(s):

Itaconic Acid ◽

Polymer Network ◽

Polymer Networks ◽

Low Ph ◽

Interpenetrating Polymer Networks ◽

Polyacrylamide Gel ◽

Swelling Properties ◽

Swelling Degree ◽

Equilibrium Swelling ◽

Carboxylic Groups

The effect of pH and temperature on the equilibrium swelling properties of PIA/PAAm semi-IPNs were investigated.Semi-IPNs based on polyacrylamide (PAAm) and poly(itaconic acid) (PIA) were prepared by two different techniques, by polymerizing itaconic acid in the presence of polyacrylamide gel (Semi-IPNs-l) and by making the polyacrylamide gel in the presence of previously synthesized poly(itaconic acid) (Semi-IPNs-ll), with different PIA/PAAm mass ratios. The equilibrium swelling degree of an ionic network depends very much on the concentration of ionisable groups. The addition of a small amount of itaconic acid dramatically changes the swelling behavior of PAAm. Increase of the ionic monomer (IA) produces swelling degrees that increase to a high extent when the pH of the buffer solution is higher than the nominal pKa values of the acid groups. Gels with higher IA content swell less than PAAm gels in low pH buffers. At low pH, when complexation due to hydrogen bonding occurs between the carboxylic groups and amide groups of acrylamide, the polymer network collapses and the swelling ratio is low. The presence of hydrogen bonds in the complexes causes additional constraints in the network, acting as a physical crosslinking and makes the network less hydrophilic, because the carboxylic groups on the PIA are occupied in the complexes. As opposed to this, the equilibrium swelling degrees change very little with pH of the solution in nonionic PAAm gel.Hydrogels exhibit continuous changes in water content as a function of temperature. The swelling degree increases with increasing temperature due to gel expansion upon warming.

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Investigation of Gel Properties of Novel Cryo-Clay-Silica Polymer Networks

Gels ◽

10.3390/gels6020011 ◽

2020 ◽

Vol 6 (2) ◽

pp. 11

Author(s):

Patrik Berg ◽

Carsten Dieter Prowald ◽

Dirk Kuckling

Keyword(s):

Tensile Strength ◽

Silica Gel ◽

Polymer Networks ◽

Gel Strength ◽

Gel Properties ◽

Swelling Properties ◽

Degree Of Swelling ◽

Swelling Kinetic ◽

Responsive Behavior ◽

Post Modification

Several methods to increase the mechanical and swelling properties of Poly(N-isopropylacrylamide) gels are known. In this study different methods were combined to systematically alter the gel properties. The combination of nanocomposite and cryo gels as well as silica post modification was used to modulate the gel strength. This new cryo-clay-silica gel based on N-isopropylacrylamide was investigated in respect to degree of swelling, kinetic of thermo responsive behavior and tensile strength. Here, the properties of new cryo-clay-silica gel were compared with properties of clay-, silica-clay and cryo-clay gels.

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Phosphates-Containing Interpenetrating Polymer Networks (IPNs) Acting as Slow Release Fertilizer Hydrogels (SRFHs) Suitable for Agricultural Applications

Materials ◽

10.3390/ma14112893 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2893

Author(s):

Agnieszka Lipowczan ◽

Andrzej W. Trochimczuk

Keyword(s):

Slow Release ◽

Polymer Networks ◽

Significant Loss ◽

Interpenetrating Polymer Networks ◽

Agricultural Field ◽

Swelling Properties ◽

Slow Release Fertilizer ◽

Phosphorus Containing ◽

Agricultural Applications ◽

Ethyl Phosphate

Novel, phosphorus-containing slow release fertilizer hydrogels (SRFHs) composed of interpenetrating polymer networks (IPNs) with very good swelling and mechanical properties have been obtained and characterized. It was found that introducing organophosphorus polymer based on a commercially available monomer, 2-methacryloyloxyethyl phosphate (MEP), as the IPN’s first component network results in much better swelling properties than for a terpolymer with acrylic acid (AAc), 2-methacryloyloxyethyl phosphate (MEP) and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) when the same weight ratios of monomers are employed. The procedure described in this paper enables the introduction of much larger amounts of phosphorus into polymer structures without significant loss of water regain ability, which is crucial in the application of such materials in the agricultural field.

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