scholarly journals Preparation and Characterization of UV-Curable Cyclohexanone-Formaldehyde Resin and Its Cured Film Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Guang Yang ◽  
Hongqiang Li ◽  
Xuejun Lai ◽  
Yi Wang ◽  
Yifu Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Formaldehyde Resin ◽  
Resonance Spectroscopy ◽  
Uv Curable ◽  
Good Thermal Stability ◽  
Distribution Index

UV-curable cyclohexanone-formaldehyde (UVCF) resin was prepared with cyclohexanone-formaldehyde (CF) resin, isophorone diisocyanate (IPDI), and pentaerythritol triacrylate (PETA) as base substance, bridging agent, and functional monomer, respectively. The structure of UVCF was characterized by Fourier transform infrared spectroscopy (FT-IR),1H-nuclear magnetic resonance spectroscopy (1H-NMR), and gel permeation chromatography (GPC). The viscosity and photopolymerization behavior of the UV-curable formulations were studied. The thermal stability and mechanical properties of the cured films were also investigated. The results showed that UVCF resin was successfully prepared, the number of average molecular weight was about 2010, and its molecular weight distribution index was 2.8. With the increase of UVCF resin content, the viscosity of the UV-curable formulations increased. After exposure to UV irradiation for 230 s, the photopolymerization conversion of the UV-curable formulations was above 80%. Moreover, when the UVCF content was 60%, the formulations had high photopolymerization rate, and the cured UVCF films showed good thermal stability and mechanical properties.

Semi-bio-based aromatic polyamides from 2,5-furandicarboxylic acid: toward high-performance polymers from renewable resources

RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87013-87020 ◽  
Author(s):  
Kaiju Luo ◽  
Yan Wang ◽  
Junrong Yu ◽  
Jing Zhu ◽  
Zuming Hu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Renewable Resources ◽  
High Performance ◽  
Good Thermal Stability ◽  
Aromatic Polyamides ◽  
High Performance Polymers ◽  
Furandicarboxylic Acid

Aromatic furanic polyamides with relatively high molecular weight were synthesized, and good thermal stability and mechanical properties were demonstrated.

Study on Preparation and Properties of Copolymer of Phenol and Acrylamide by Enzyme Catalyzed Polymerization

2010 ◽  
Vol 129-131 ◽  
pp. 872-876
Author(s):  
Yan Fen Ma ◽  
Sheng Hua Lv ◽  
Gang Liu ◽  
Jian Ping Duan ◽  
Rui Jun Gao
Keyword(s):  
Molecular Weight ◽  
Fourier Transform ◽  
Horseradish Peroxidase ◽  
Ftir Spectroscopy ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Fourier Transform Infrared ◽  
Monomer Composition ◽  
Gel Permeation ◽  
Distribution Index

The copolymer of phenol and acrylamide was synthesized by copolymerization using horseradish peroxidase (HRP)/H2O2 as catalyst. The effect of monomer composition on the copolymer tanning agent properties was investigated. The structure of the copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy. The molecular weight was determined by gel permeation chromatography (GPC). The result shows that the average molecular weight of the copolymer is about 1900. Its molecule distribution index is much narrower. The copolymer was used as tanning agent, the result shows that the applied leather is excellent in softness and dyeing.

Improving the Thermal and Mechanical Properties of Phenolic Fiber over Boron Modified High-Ortho Phenolic Resin

2020 ◽  
pp. 095400832097675
Author(s):  
Yu Ren ◽  
Xu Lin ◽  
Zhengjun Shi ◽  
Yunwu Zheng ◽  
Jianxiang Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Boric Acid ◽  
Melt Spinning ◽  
Phenolic Resin ◽  
Raw Materials ◽  
Fiber Strength ◽  
Average Molecular Weight ◽  
P Value

Boron-modified high-ortho phenolic resins (BPRs) were prepared under normal pressure by using phenol and formaldehyde as raw materials, zinc acetate, and oxalic acid as catalysts, and boric acid as a modifier. Boron-modified phenolic fibers (BPFs) were prepared by melt spinning and curing in a mixture of formaldehyde and hydrochloric acid, followed by a heat treatment under high temperature. The structure, ortho–para ratio (O/P), molecular weight and distribution, spinnability, thermal stability, fiber strength, and morphology of the resins were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and fiber strength testing. The results showed that the addition of boric acid reduced the ortho reaction of the synthetic resin and the O/P value of phenolic resin. When the content of boric acid was 3 wt%, the thermal stability was the best, the O/P value was up to 3.26, and the weight average molecular weight (Mw) was 18745 g/mol. In Compared with the unmodified resin, the mass loss was increased by 33.7%, and finally the carbon yield was 51.2%. The tensile strength of the fibers reached 187.2 MPa and the elongation at break was 10.5%. By introducing boron into the molecular chain, the structure of the resin was improved, and the thermal stability and mechanical properties of the fibers were improved.

scholarly journals POLYMER ADDITIVE EFFECT ON THE STRUCTURAL AND MECHANICAL PROPERTIES OF THE ORGANIC PART OF OIL BITUMINOUS ROCK

2020 ◽  
Vol 5 (443) ◽  
pp. 141-150
Author(s):  
Narmanova Roza Abdibekovna, ◽  
◽  
Bishimbayev Valikhan Kozykeevich, ◽  
Tapalova Anipa Seidalievna, ◽  
Appazov Nurbol Orynbassaruly, ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Average Molecular Weight ◽  
Maximum Yield ◽  
Gel Permeation Chromatography ◽  
Weight Fraction ◽  
Polymer Additive ◽  
Atactic Polypropylene ◽  
Organic Part ◽  
Bituminous Rock

The article presents the results of gas chromatographic analysis method of the organic part of oil bituminous rock and the results from the analysis of the molecular weight distribution of atactic polypropylene carried out using reverse gel-permeation chromatography. The research results of the structural and mechanical properties of the bitumen part of oil bituminous rock (OBR) of the Iman-Kara deposit, atactic polypropylene (APP) and compositions based on them, carried out on the instrument Reotest 2.1, are also presented herein. It has been determined that the organic part of OBR of the Iman-Kara deposit mainly consists of oxygen-containing organic compounds with additions of heteroatomic structures (sulfur, haloids and nitrogen) with a weight fraction of 53.97%. According to the chromatogram of the molecularly-mass distributed atactic polypropylene, it is found that the average time of fraction maximum yield is 11.4 minutes, the corresponding value of logarithm of the average molecular weight Lg(M) equals to 5.5. Accordingly, the average molecular weight of fraction M is 400. The change patterns of the rheological properties of the organic part of OBR, atactic polypropylene and compositions based on them are described. It has been established that the addition of APP to the organic part of OBR creates a disperse system in which the particles of a polymer additive that are swollen due to oily components are dispersed in the bitumen medium. At the same time, mechanical properties such as elasticity and heat resistance of the organic part of oil bituminous rock are improved. These properties can be shown only with the optimum quantity of APP, when their concentration is such that they form an uninterrupted net structure. The influence patterns of APP on the structure of the organic part of OBR defined in the process of experiments can also be used in further experiments during development of various types of waterproofing materials and coatings.

Preparation of Lactic Acid Based Polyurethanes Modified by Castor Oil

2008 ◽  
Vol 47-50 ◽  
pp. 1458-1461 ◽  
Author(s):  
Biao Fu ◽  
Lin Xiao ◽  
Long Jiang Yu ◽  
Guang Yang
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Lactic Acid ◽  
Castor Oil ◽  
Average Molecular Weight ◽  
Tensile Modulus ◽  
Gel Permeation Chromatography ◽  
Elongation At Break ◽  
Gel Permeation ◽  
Soft Tissue Engineering

A series of biodegradable lactic acid based Polyurethanes modified by castor oil (PLBA-PUs) have been successfully prepared by using a two steps method as follow: Firstly prepolymers with hydroxyl terminated are synthesized by copolymerization of L-lactic acid and 1, 4-butandiol (BD), and then react with castor oil (C.O.) and hexamethylene diisocynate (HDI). The effects of BD/LA monomer ration and C.O./prepolymers mole ratio on the molecular weight and mechanical properties of PLBA-PUs are investigated. The polymers obtained are characterized by gel permeation chromatography, fourier transform infrared spectroscopy, 13C NMR, differential scanning calorimeter (DSC) and tensile testing. Their average molecular weight is over 280,000. They display excellent mechanical properties, such as a tensile strength as high as 31MPa, a tensile modulus as low as 20 MPa, and an elongation at break of 176%. Due to the biocompatibility, these PUs could find applications in biomedical fields, such as soft-tissue engineering.

Effect of Heat Treatment on Mechanical Properties of ECAPed 7075 Aluminum Alloy

2013 ◽  
Vol 829 ◽  
pp. 62-66 ◽  
Author(s):  
Alireza Fallahi ◽  
Hossein Hosseini-Toudeshky ◽  
Seyed Mahmoud Ghalehbandi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Solution Treatment ◽  
7075 Aluminum Alloy ◽  
Ecap Processing ◽  
Good Thermal Stability ◽  
7075 Alloy

It is the objective of this study to investigate the effect of ECAP processing and heat treatment on the mechanical properties of the UFG 7075 alloy. Also the effect of post ECAP heat treatment is investigated. The alloy is processed by ECAP after annealing as well as solution treatment to produce an UFG structure. Furthermore mechanical properties and their variations during annealing and aging are investigated. The hardness of the pre-ECAP annealed and the pre-ECAP solutionised 7075 aluminum alloy has increased significantly compared with that of the CG sample. Also hardness of ECAPed specimen has not experienced significant changes in post-ECAP heat treatment and indicated that the alloy had approximately good thermal stability.

scholarly journals Valonea Tannin: Tyrosinase Inhibition Activity, Structural Elucidation and Insights into the Inhibition Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2747
Author(s):  
Jiaman Liu ◽  
Yuqing Liu ◽  
Xiaofeng He ◽  
Bo Teng ◽  
Jacqui M. McRae
Keyword(s):  
Molecular Weight ◽  
Structure Function ◽  
Hydrophobic Interactions ◽  
Average Molecular Weight ◽  
Commercial Application ◽  
Inhibition Mechanism ◽  
Resonance Spectroscopy ◽  
Inhibition Activity ◽  
Tyrosinase Inhibition ◽  
Function Activity

Valonea tannin is a natural product readily extracted from acorn shells that has been suggested to have potential skin whitening properties. This study investigated the tyrosinase inhibition activity of extracted valonea tannin and the associated structure–function activity. Nuclear magnetic resonance spectroscopy and molecular weight analysis with gel permeation chromatography revealed that valonea tannin could be characterized as a hydrolysable tannin with galloyl, hexahydroxydiphenoyl and open formed-glucose moieties and an average molecular weight of 3042 ± 15 Da. Tyrosinase inhibition assays demonstrated that valonea tannin was 334 times more effective than gallic acid and 3.4 times more effective than tannic acid, which may relate to the larger molecular size. Kinetic studies of the inhibition reactions indicated that valonea tannin provided tyrosinase inhibition through mixed competitive–uncompetitive way. Stern–Volmer fitted fluorescence quenching analysis, isothermal titration calorimetry analysis and in silico molecule docking showed valonea tannin non-selectively bound to the surface of tyrosinase via hydrogen bonds and hydrophobic interactions. Inductively coupled plasma-optical emission spectroscopy and free radical scavenging assays indicated the valonea tannin had copper ion chelating and antioxidant ability, which may also contribute to inhibition activity. These results demonstrated the structure–function activity of valonea tannin as a highly effective natural tyrosinase inhibitor that may have commercial application in dermatological medicines or cosmetic products.

Probing the molecular weights of sweetgum and pine kraft lignin fractions

TAPPI Journal ◽  
2021 ◽  
Vol 20 (6) ◽  
pp. 381-391
Author(s):  
JULIANA M. JARDIM ◽  
PETER W. HART ◽  
LUCIAN LUCIA ◽  
HASAN JAMEEL
Keyword(s):  
Molecular Weight ◽  
Black Liquor ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Systematic Investigation ◽  
Kraft Pulping ◽  
Molecular Weights ◽  
Lignin Recovery ◽  
Lignin Reactivity ◽  
Kinetics Of

The present investigation undertook a systematic investigation of the molecular weight (MW) of kraft lignins throughout the pulping process to establish a correlation between MW and lignin recovery at different extents of the kraft pulping process. The evaluation of MW is crucial for lignin characterization and utilization, since it is known to influence the kinetics of lignin reactivity and its resultant physicochemical properties. Sweetgum and pine lignins precipitated from black liquor at different pHs (9.5 and 2.5) and different extents of kraft pulping (30–150 min) were the subject of this effort. Gel permeation chromatography (GPC) was used to deter- mine the number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity of the lignin samples. It was shown that the MW of lignins from both feedstocks follow gel degradation theory; that is, at the onset of the kraft pulping process low molecular weightlignins were obtained, and as pulping progressed, the molecular weight peaked and subsequently decreased. An important finding was that acetobromination was shown to be a more effective derivatization technique for carbohydrates containing lignins than acetylation, the technique typically used for derivatization of lignin.

Alternative Tanning Agent for Leather Industry from a Sustainable Source

2021 ◽  
Vol 116 (3) ◽  
Author(s):  
Cigdem Kilicarislan Ozkan ◽  
Hasan Ozgunay
Keyword(s):  
Molecular Weight ◽  
Corn Starch ◽  
Periodate Oxidation ◽  
Gel Permeation Chromatography ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Leather Industry ◽  
Sodium Metaperiodate ◽  
Gel Permeation ◽  
Aldehyde Content

Dialdehyde starches with different aldehyde content from native corn starch were prepared by sodium periodate oxidation to be used as a tanning agent in leather making. For this purpose, native corn starch was oxidized with sodium metaperiodate in different molar ratios. After oxidation processes, the yields, solubility in water and aldehyde contents of the obtained dialdehyde starches were determined as well as structure characterizations by Proton Nuclear Magnetic Resonance Spectroscopy, Fourier Transform Infrared Spectroscopy and Gel Permeation Chromatography. Evaluating the gel permeation chromatography data, the dialdehyde starch samples which were thought to be in appropriate molecular weight/size to penetrate into skin fibers were selected to be used in the tanning process. Their tanning abilities were evaluated by investigating hydrothermal stabilities, filling and fiber isolation characteristics and physical properties determined by mechanical tests and organoleptically. From the evaluation of the results, it was revealed that sodium metaperiodate oxidized starches which have appropriate molecular weight and adequate aldehyde content has a remarkable tanning effect and can be utilized as a tanning agent with the advantages of not necessitating pickling process which means saving time and simplifying the production but more importantly offering an important advantage from an environmental point of view.

scholarly journals Characterisation of Sequential Solvent Fractionation and Base-catalysed Depolymerisation of Treated Alkali Lignin

BioResources ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. 4137-4151 ◽  
Author(s):  
Aikfei Ang ◽  
Zaidon Ashaari ◽  
Edi Suhaimi Bakar ◽  
Nor Azowa Ibrahim
Keyword(s):  
Molecular Weight ◽  
Chemical Structure ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Solubility Parameters ◽  
Low Molecular Weight ◽  
Sequential Fractionation ◽  
Weight Average Molecular Weight ◽  
Solvent Fractionation ◽  
Alkali Lignin

An alkali lignin (OL) with a weight-average molecular weight (Mw) of 11646 g/mol was used to prepare low-molecular weight lignin for resin synthesis. The low-molecular weight lignin feedstock was obtained via base-catalysed depolymerisation (BCD) treatments at different combined severity factors. Sequential fractionation of the OL and BCD-treated lignins using organic solvents with different Hildebrand solubility parameters were used to alter the homogeneity of the OL. The yield and properties of OL itself and OL and BCD-treated OL dissolved in propan-1-ol (F1), ethanol (F2), and methanol (F3) were determined. Regardless of the treatment applied, a small amount of OL was dissolved in F1 and F2. The BCD treatment did not increase the yield of F1 but did increase the yields of F2 and F3. Gel permeation chromatography (GPC) showed that the repolymerization reaction occurred in F3 for all BCD-treated OL, so these lignins were not suitable for use as feedstocks for resin production. The GPC, 13Carbon-nuclear magnetic resonance, and Fourier transform infrared spectroscopy analyses confirmed that the F3 in OL exhibited the optimum yield, molecular weight distribution, and chemical structure suitable for use as feedstocks for resin synthesis.

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