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

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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Preparation and Swelling Inhibition of Polyammonium

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.482-484.1317 ◽

2012 ◽

Vol 482-484 ◽

pp. 1317-1320

Author(s):

Qiang Deng ◽

Deng Feng Wei ◽

Zheng Qin Ye ◽

Jin Fang Xu

Keyword(s):

Inorganic Salts ◽

Cross Linking ◽

Cross Link ◽

Swelling Properties ◽

Swelling Agent ◽

Dimethyl Amine

A new anti-swelling agent was synthesized by polymerizing epichlorohydrin and dimethyl amine polymer. The swelling inhibition properties were investigated over clay and shale. It was found that the clay inhibition of swelling properties was greatly enhanced compared with common inorganic salts. However, to shale, the swelling properties did not inhibited efficiently by using prepared polymers. Furthermore, the influence of cross linking of polyammonium to the swelling ability of prepared polymer has been also carried out by using triethylenetetramine cross linking agent. In the case of shale, the swelling inhibit properties was improved after cross link, while opposite swelling effect was observed over clay.

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Quasi-Solid Semi-Interpenetrating Polymer Networks as Electrolytes: Part I. Dependence of Physicochemical Characteristics and Ion Conduction Behavior on Matrix Composition, Cross-Link Density, Chain Length between Cross-Links, Molecular Entanglements, Charge Carrier Concentration, and Nature of Anion

The Journal of Physical Chemistry C ◽

10.1021/jp409533r ◽

2013 ◽

Vol 118 (1) ◽

pp. 159-174 ◽

Cited By ~ 16

Author(s):

Nimai Bar ◽

Kota Ramanjaneyulu ◽

Pratyay Basak

Keyword(s):

Polymer Networks ◽

Physicochemical Characteristics ◽

Charge Carrier Concentration ◽

Interpenetrating Polymer Networks ◽

Matrix Composition ◽

Cross Link ◽

Link Density ◽

Conduction Behavior ◽

Cross Links ◽

Cross Link Density

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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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