scholarly journals Effect of Colloidal Fillers on the Cross-Linking of a UV-Curable Polymer:  Gel Point Rheology and the Winter−Chambon Criterion

2001 ◽  
Vol 34 (13) ◽  
pp. 4526-4533 ◽  
Author(s):  
Bor-Sen Chiou ◽  
Srinivasa R. Raghavan ◽  
Saad A. Khan
Keyword(s):  
Cross Linking ◽  
Gel Point ◽  
Polymer Gel ◽  
Uv Curable ◽  
The Cross

6. Liveliness

2020 ◽  
pp. 115-134
Author(s):  
Tom McLeish
Keyword(s):  
Liquid Crystals ◽  
Soft Matter ◽  
Active Form ◽  
Cross Linking ◽  
Polymer Gel ◽  
Biologically Inspired ◽  
Active Liquid ◽  
Cross Links ◽  
The Cross ◽  
Colloid Nanoparticles

‘Liveliness’ studies the new biologically inspired field of active soft matter. Almost any type of soft matter possesses an active form. Using myosin corresponds to making the cross-links of a polymer gel active. However, polymerization itself can be actively driven, as well as the cross-linking between polymers. Bacteria are, within this perspective, an active form of colloid—nanoparticles that can swim. As their shape becomes highly anisotropic, they generate the notion of ‘active liquid crystals’.

Monitoring the Cross-Linking of a HPAm/Cr(III) Acetate Polymer Gel Using1H NMR, UV Spectrophotometry, Bottle Testing, and Rheology

2007 ◽  
Vol 12 (5) ◽  
pp. 339-357 ◽  
Author(s):  
Silvia Magnolia Vargas-Vasquez ◽  
Laura Beatriz Romero-Zerón ◽  
Rodney Macgregor ◽  
Senthil Gopalakrishnan
Keyword(s):  
Cross Linking ◽  
Uv Spectrophotometry ◽  
Polymer Gel ◽  
The Cross

scholarly journals One-Step Synthesis of Novel Renewable Vegetable Oil-Based Acrylate Prepolymers and Their Application in UV-Curable Coatings

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1165 ◽  
Author(s):  
Yupei Su ◽  
Hai Lin ◽  
Shuting Zhang ◽  
Zhuohong Yang ◽  
Teng Yuan
Keyword(s):  
Double Bond ◽  
Vegetable Oil ◽  
Reaction Rate ◽  
Rapid Development ◽  
Practical Significance ◽  
Organic Polymer ◽  
Cross Linking ◽  
Uv Curable ◽  
One Step ◽  
The Cross

With the rapid development of social economy, problems such as volatile organic compound (VOC) pollution and the excessive consumption of global petroleum resources have become increasingly prominent. People are beginning to realize that these problems not only affect the ecological environment, but also hinder the development of the organic polymer material industry based on raw fossil materials. Therefore, the modification and application of bio-based materials are of theoretical and practical significance. In this study, a series of vegetable oil-based acrylate prepolymers were synthesized by one-step acrylation using palm oil, olive oil, peanut oil, rapeseed oil, corn oil, canola oil, and grapeseed oil as raw materials, and the effect of different double bond contents on the product structure and grafting rate was investigated. Furthermore, the as-prepared vegetable oil-based acrylate prepolymers, polyurethane acrylate (PUA-2665), trimethylolpropane triacrylate (TMPTA), and photoinitiator (PI-1173) were mixed thoroughly to prepare ultraviolet (UV)-curable films. The effect of different grafting numbers on the properties of these films was investigated. The results showed that as the degree of unsaturation increased, the acrylate grafting number and the cross-linking density increased, although the acrylation (grafting reaction) rate decreased. The reason was mainly because increasing the double bond content could accelerate the reaction rate, while the grafted acrylic groups had a steric hindrance effect to prevent the adjacent double bonds from participating in the reaction. Furthermore, the increase in grafting number brought about the increase in the structural functionality of prepolymers and the cross-linking density of cured films, which led to the enhancement in the thermal (glass transition temperature) and mechanical (tensile strength, Young’s modulus) properties of the cured films.

scholarly journals Plugging mechanisms of polymer gel used for hydraulic fracture water shutoff

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 411-422
Author(s):  
Song Zhang ◽  
Falin Wei ◽  
Pingde Liu ◽  
Liming Shao ◽  
Weitao Li
Keyword(s):  
Hydraulic Fracture ◽  
Physical Simulation ◽  
Distribution Patterns ◽  
Cross Linking ◽  
Polymer Gel ◽  
Gel Layer ◽  
The Matrix ◽  
The Cross ◽  
The Difference ◽  
Flow Leak

AbstractThe performance of polymer gel to plug a hydraulic fracture is greatly affected by its distribution patterns and gelling effect. In this study, the migration of a gel plugging agent in a fracture and its plugging after gelling were investigated by physical simulation experiments. In addition, the distribution patterns of the gel plugging agent and its plugging mechanism after gelling were investigated in detail. The results of this study revealed that the migration flowing behavior of the gel solution in a fracture can be divided into three streams: fracture flow, leak off flow, and matrix flow. Such behavior distributed the gel in three different patterns after gelling: gel clusters in the fracture, gel layer on the fracture surface, and dispersed gel lumps in the matrix pores-throats. Because of the leak off flow and the difference in components, the gel solution has apparent disproportional leak off–diffusion of components during its migration in a fracture, with less polymer molecules and loss of more cross-linking agent ions. The leak off of the cross-linking agent significantly deteriorates the gelling strength of the polymer gel, affecting its performance to plug a hydraulic fracture. The results also show that when the normalized concentration of the cross-linking agent ions in a fracture is less than 0.6, gel fails to plug the fracture effectively after gelling. When gelling was carried out by in situ cross-linking, polymer gel provided more satisfactory plugging performance than the gelling via ground pre-cross-linking.

scholarly journals The Use of the ATD Technique to Measure the Gelation Time of Epoxy Resins

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6022
Author(s):  
Jakub Smoleń ◽  
Piotr Olesik ◽  
Paweł Gradoń ◽  
Mateusz Chudy ◽  
Bogusław Mendala ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Epoxy Resins ◽  
Gelation Time ◽  
Graphite Powder ◽  
Cross Linking ◽  
Gel Point ◽  
Curing Process ◽  
Carbon Particles ◽  
The Cross ◽  
The Stability

In this paper, we investigated the thermodynamics of the resin curing process, when it was a part of composition with graphite powder and cut carbon fibers, to precisely determine the time and temperature of gelation. The material for the research is a set of commercial epoxy resins with a gelation time not exceeding 100 min. The curing process was characterized for the neat resins and for resins with 10% by weight of flake graphite and cut carbon fibers. The results recorded in the analysis of temperature derivative (ATD) method unequivocally showed that the largest first derivative registered during the test is the gel point of the resin. The innovative approach to measuring the gelation time of resins facilitates the measurements while ensuring the stability of the curing process compared to the normative tests that introduce mechanical interaction. In addition, it was found during the research that the introduction of 10% by weight of carbon particles in the form of graphite and cut carbon fibers rather shortens the gelation time and lowers the temperature peak due to the effective absorption and storage of heat from the cross-linking system. The inhibiting (or accelerating) action of fillers is probably dependent on chemical activity of the cross-linking system.

scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

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