Dual-curable isocyanate crosslinking agents blocked by methacrylate-functionalized pyrazoles with lower curing temperature

Abstract Mono- and bismaleimides were evaluated as curing agents to determine the effect of structure on crosslinking ability. Activity of N-phenylmaleimide derivatives (monomaleimides) as crosslinking agents is highly dependent upon the substituent on the phenyl group. Activity of bismaleimides is likewise affected by the nature of the moiety connecting the maleimide rings. Isomaleimides and itaconimides are less effective curatives. Initiators for maleimide cures include peroxides and sulfur accelerators of the thiazole type. Saturated and unsaturated hydrocarbon rubbers, except those containing a high percentage of isobutylene units, are vulcanized by a maleimide-initiator system. One of the attractive features of a maleimide curing system is that physical properties of the cured rubbers are independent of curing temperature. Further, these vulcanizates have the good aging characteristics typical of nonsulfur-cured vulcanizates. In contrast to sulfur vulcanization, the maleimide curing systems do not markedly affect the ability of elastomers to crystallize when stretched. Therefore, the T50 test cannot be used to assess the state of cure of maleimide-natural rubber vulcanizates. Maleimides containing an appropriate second functional group can be used as self-accelerating curing agents or as adhesives.

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Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

Jurnal Intake : Jurnal Penelitian Ilmu Teknik dan Terapan ◽

10.32492/jintake.v9i2.776 ◽

2018 ◽

Vol 9 (2) ◽

pp. 67-73

Author(s):

M Zainul Arifin

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Curing Temperature ◽

Test Results ◽

Concrete Compressive Strength ◽

Normal Concrete ◽

Astm Method ◽

Additive Type ◽

Composition Variation ◽

Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

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SINTESIS DAN MODIFIKASI STRUKTUR DAN PORI MEMBRAN KITOSAN TERCROSSLINK UNTUK STERILISASI MEDIA PERTUMBUHAN BAKTERI

Sains & Teknologi ◽

10.24123/jst.v3i2.2283 ◽

2019 ◽

Vol 3 (2) ◽

pp. 27

Author(s):

Emma Savitri ◽

Natalia Suseno ◽

Tokok Adiarto

Keyword(s):

Tensile Strength ◽

Chitosan Solution ◽

Curing Temperature ◽

Growth Media ◽

Optimum Conditions ◽

Separation Processes ◽

Crosslinking Process ◽

Chitosan Membrane ◽

Chitosan Membranes ◽

Crosslinked Chitosan

Many mass-transfer applications have used chitosan membrane in separation processes. This research applied crosslinked chitosan membrane to sterillize bacterial growth media. Chitosan membranes having 79 % DD were produced by casting and drying chitosan solution. The images of the membrane were characterized by SEM and other characterizations such as permeability, permselectivity and tensile strength were investigated. The flux increased with longer submersion period but the rejection decreased. Otherwise, the flux decreased and rejection increased in line with an increase in curing temperature. Tensile strength increased with the increase of submersion period and curing temperature. The optimum conditions of crosslinking process are 2 hours of submersion periods and curing temperature at 90 oC. It gives flux 5.8930 L/jam.m2, rejection 97.47 % and tensile strength 49640 kN/m2

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Plastics. Organic-perester crosslinking agents for unsaturated-polyester thermosetting materials. Determination of active-oxygen content

10.3403/01823450 ◽

1999 ◽

Keyword(s):

Oxygen Content ◽

Unsaturated Polyester ◽

Active Oxygen ◽

Crosslinking Agents

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The Effect of Crosslinking Agents on the Properties of Type II Collagen Biomaterials

Materiale Plastice ◽

10.37358/mp.20.4.5416 ◽

2021 ◽

Vol 57 (4) ◽

pp. 166-180

Author(s):

Maria-Minodora Marin ◽

Madalina Georgiana Albu Kaya ◽

George Mihail Vlasceanu ◽

Jana Ghitman ◽

Ionut Cristian Radu ◽

...

Keyword(s):

Research Work ◽

Cartilage Tissue Engineering ◽

Chemical Properties ◽

Cartilage Regeneration ◽

Type Ii Collagen ◽

Biomechanical Properties ◽

Cartilage Tissue ◽

Cross Linking ◽

Type Ii ◽

Crosslinking Agents

Type II collagen has been perceived as the indispensable element and plays a crucial role in cartilage tissue engineering. Thus, materials based on type II collagen have drawn farther attention in both academic and research for developing new systems for the cartilage regeneration. The disadvantage of using type II collagen as a biomaterial for tissue repairing is its reduced biomechanical properties. This can be solved by physical, enzymatic or chemical cross-linking processes, which provide biomaterials with the required mechanical properties for medical applications. To enhance type II collagen properties, crosslinked collagen scaffolds with different cross-linking agents were prepared by freeze-drying technique. The present research work studied the synthesis of type II collagen biomaterials with and without crosslinking agents. Scaffolds morphology was observed by MicroCT, showing in all cases an appropriate microstructure for biological applications, and the mechanical studies were performed using compressive tests. DSC showed an increase in denaturation temperature with an increase in cross-linking agent concentration. FTIR suggested that the secondary structure of collagen is not affected after the cross-linking; supplementary, to confirm the characteristic triple-helix conformation of collagen, the CD investigation was performed. The results showed that the physical-chemical properties of type II collagen were improved by cross-linking treatments.

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Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

Journal of Advanced Transportation ◽

10.1155/2020/2469436 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Yongli Xu ◽

Guang Yang ◽

Hongyuan Zhao

Keyword(s):

Compressive Strength ◽

Low Temperature ◽

Curing Temperature ◽

Strength Development ◽

Construction Process ◽

Strength Gain ◽

Estimation Model ◽

Maturity Method ◽

Temperature Ranges ◽

Natural Temperature

For cement-based materials, the curing temperature determines the strength gain rate and the value of compressive strength. In this paper, the 5% cement-stabilized macadam mixture is used. Three indoor controlled temperature curing and one outdoor natural curing scenarios are designed and implemented to study the strength development scenario law of compressive strength, and they are standard temperature curing (20°C), constant low temperature curing (10°C), day interaction temperature curing (varying from 6°C to 16°C), and one outdoor natural temperature curing (in which the air temperature ranges from 4°C to 20°C). Finally, based on the maturity method, the maturity-strength estimation model is obtained by using and analyzing the data collected from the indoor tests. The model is proved with high accuracy based on the validated results obtained from the data of outdoor tests. This research provides technical support for the construction of cement-stabilized macadam in regions with low temperature, which is beneficial in the construction process and quality control.

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Terephthalaldehyde as better crosslinking agent in crosslinked chitosan hydrogel for selective removal of anionic dyes

New Journal of Chemistry ◽

10.1039/d0nj05758d ◽

2021 ◽

Author(s):

Madhvi Garg ◽

Navneet Bhullar ◽

Bharat Bajaj ◽

Dhiraj Sud

Keyword(s):

Crosslinking Agent ◽

Selective Removal ◽

Synthetic Dyes ◽

Anionic Dyes ◽

Chitosan Hydrogel ◽

Ultrasound Radiation ◽

Radiation Induced ◽

Crosslinked Chitosan ◽

Chitosan Hydrogels ◽

Crosslinking Agents

The present manuscript reports the ultrasound radiation induced synthesis of grafted chitosan hydrogels (CAAT and CAAG) using terephthalaldehyde/glutaraldehyde as crosslinking agents and its application for removal of synthetic dyes from...

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Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽

10.3390/ma14071611 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1611

Author(s):

Gintautas Skripkiūnas ◽

Asta Kičaitė ◽

Harald Justnes ◽

Ina Pundienė

Keyword(s):

Compressive Strength ◽

Cement Paste ◽

Setting Time ◽

Calcium Nitrate ◽

Curing Temperature ◽

Hardened Concrete ◽

Cement Pastes ◽

Initial Setting Time ◽

Initial Setting ◽

Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

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Role of Curing Temperature of Poly(Glycerol Sebacate) Substrates on Protein-Cell Interaction and Early Cell Adhesion

Polymers ◽

10.3390/polym13030382 ◽

2021 ◽

Vol 13 (3) ◽

pp. 382

Author(s):

Rubén Martín-Cabezuelo ◽

José Carlos Rodríguez-Hernández ◽

Guillermo Vilariño-Feltrer ◽

Ana Vallés-Lluch

Keyword(s):

Protein Interactions ◽

Chemical Properties ◽

Focal Adhesions ◽

Collagen Type I ◽

Inhibitory Effect ◽

Synthesis Temperature ◽

Curing Temperature ◽

Cell Protein ◽

Preliminary Treatment ◽

Type I

A novel procedure to obtain smooth, continuous polymeric surfaces from poly(glycerol sebacate) (PGS) has been developed with the spin-coating technique. This method proves useful for separating the effect of the chemistry and morphology of the networks (that can be obtained by varying the synthesis parameters) on cell-protein-substrate interactions from that of structural variables. Solutions of the PGS pre-polymer can be spin-coated, to then be cured. Curing under variable temperatures has been shown to lead to PGS networks with different chemical properties and topographies, conditioning their use as a biomaterial. Particularly, higher synthesis temperatures yield denser networks with fewer polar terminal groups available on the surface. Material-protein interactions were characterised by using extracellular matrix proteins such as fibronectin (Fn) and collagen type I (Col I), to unveil the biological interface profile of PGS substrates. To that end, atomic force microscopy (AFM) images and quantification of protein adsorbed in single, sequential and competitive protein incubations were used. Results reveal that Fn is adsorbed in the form of clusters, while Col I forms a characteristic fibrillar network. Fn has an inhibitory effect when incubated prior to Col I. Human umbilical endothelial cells (HUVECs) were also cultured on PGS surfaces to reveal the effect of synthesis temperature on cell behaviour. To this effect, early focal adhesions (FAs) were analysed using immunofluorescence techniques. In light of the results, 130 °C seems to be the optimal curing temperature since a preliminary treatment with Col I or a Fn:Col I solution facilitates the formation of early focal adhesions and growth of HUVECs.

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Machine Learning Approaches for Prediction of the Compressive Strength of Alkali Activated Termite Mound Soil

Applied Sciences ◽

10.3390/app11114754 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4754

Author(s):

Assia Aboubakar Mahamat ◽

Moussa Mahamat Boukar ◽

Nurudeen Mahmud Ibrahim ◽

Tido Tiwa Stanislas ◽

Numfor Linda Bih ◽

...

Keyword(s):

Compressive Strength ◽

Construction Materials ◽

Curing Temperature ◽

Sustainable Construction ◽

Support Vector ◽

Learning Approaches ◽

Artificial Neural Network Ann ◽

Curing Regime ◽

Alkali Activated

Earth-based materials have shown promise in the development of ecofriendly and sustainable construction materials. However, their unconventional usage in the construction field makes the estimation of their properties difficult and inaccurate. Often, the determination of their properties is conducted based on a conventional materials procedure. Hence, there is inaccuracy in understanding the properties of the unconventional materials. To obtain more accurate properties, a support vector machine (SVM), artificial neural network (ANN) and linear regression (LR) were used to predict the compressive strength of the alkali-activated termite soil. In this study, factors such as activator concentration, Si/Al, initial curing temperature, water absorption, weight and curing regime were used as input parameters due to their significant effect in the compressive strength. The experimental results depict that SVM outperforms ANN and LR in terms of R2 score and root mean square error (RMSE).

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