Synthesis and properties of a benzoxazine monomer containing maleimide and biphenyl groups

2021 ◽  
pp. 095400832199674
Author(s):  
Tao Guo ◽  
Yang Fan ◽  
Chang Bo ◽  
Zhang Qi ◽  
Han Tao ◽  
...  
Keyword(s):  
Weight Loss ◽  
Loss Rate ◽  
Proton Nuclear Magnetic Resonance ◽  
Significant Weight Loss ◽  
Scanning Calorimetry ◽  
Weight Loss Rate ◽  
Reaction Heat ◽  
H Nmr ◽  
Curing Reaction ◽  
Dsc Curves

Benzoxazine resin exhibits excellent properties and is widely used in many fields. Herein, the synthesis of a novel compound, the bis(2,4-dihydro-2 H-3-(4- N-maleimido)phenyl-1,3-benzoxazinyl)biphenyl (BMIPBB), has been reported, which was synthesized by reacting N-(4-aminophenyl)maleimide (APMI), formaldehyde, and 4,4’-dihydroxybiphenyl. 1,3,5-three(4-(maleimido)phenyl)-1,3,5-triazine (TMIPT) was formed as an intermediate during the reaction. The proton nuclear magnetic resonance (1H-NMR) and Fourier transform-infrared (FTIR) spectroscopy experiments were conducted to determine the structure of BMIPBB. BMIPBB was obtained as a reddish-brown solid in 40.1% yield. The thermal properties of BMIPBB were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Analysis of the DSC curves revealed that the broad peak representing the release of curing reaction heat appeared in the temperature range of 140–330°C. The peak temperature was 242.59°C and the heat of the reaction was 393.82 J/g, indicating that the rate of the curing reaction was low and the heat of the reaction was high. Analysis of the TGA results revealed that the weight loss rate was 5% at 110°C. The monomer exhibited a significant weight loss in the range of 320–500°C. The compound lost 50% of its weight at a temperature of 427°C.

scholarly journals Factors Affecting Post-surgical Body Weight Loss Rate of Patients with Colorectal Cancer

2018 ◽  
Vol 33 (4) ◽  
pp. 605-609
Author(s):  
Hiroki YABE ◽  
Mizuki TSUKAMOTO ◽  
Shihomi TAKEUCHI ◽  
Sayaka ITO ◽  
Kan OMI ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Weight Loss ◽  
Body Weight ◽  
Loss Rate ◽  
Body Weight Loss ◽  
Weight Loss Rate ◽  
Factors Affecting

scholarly journals Biocontrol of Pear Postharvest Decay by Kombucha

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Junping TAN ◽  
Xian ZHOU ◽  
Shuiyuan CHENG ◽  
Zexiong CHEN ◽  
Yuanyuan GOU ◽  
...  
Keyword(s):  
Weight Loss ◽  
Electric Conductivity ◽  
Room Temperature ◽  
Loss Rate ◽  
Economic Benefits ◽  
Control Group ◽  
Pear Fruit ◽  
Weight Loss Rate ◽  
Post Harvest ◽  
Mda Content

Kombucha is sweetened, slightly alcoholic, and lightly effervescent tea drink. Its acidity inhibits the growth of harmful bacteria. Here, we studied effect of kombucha on post-harvest preservation of pear. The Hosui pears were soaked with the kombucha for 15 minutes, and in distilled water as the control, respectively. Superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), hydrogen peroxide (H2O2), proline content, electric conductivity, weight loss rate and good fruit rate in pear were measured during storage at room temperature. The results showed that the kombucha could effectively prolong the storage time of pear fruit. The fruit quality of the treated group was 1.5 times higher than that of the control pear fruit when stored at room temperature for 18 days. The weight loss rate, MDA content and electric conductivity of the treatment group were lower than those of the control group during the whole storage period, indicating that kombucha can inhibit the transformation of polysaccharides such as starch and pectin, and delay the degradation of nutrients in the fruit, resulting in a decrease in weight loss rate, inhibition of membrane lipid peroxidation, reducing MDA content, electric conductivity, maintaining cell membrane stability, delaying pear fruit senescence. Kombucha can inhibit the content of H2O2 and proline, increase the activity of POD and SOD increase the storage stability of fruits. The purpose of this study was to elucidate the physiological mechanism of post-harvest preservation of pear by kombucha. The use of kombucha can prolong the supply period of pear, increase economic benefits and expand the market of pear.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Exposure Test Results of Lu2Si2O7 in Combustion Gas Flow at High Temperature and High Speed

2004 ◽  
Author(s):  
Isao Yuri ◽  
Tohru Hisamatsu ◽  
Shunkichi Ueno ◽  
Tatsuki Ohji
Keyword(s):  
Weight Loss ◽  
Water Vapor ◽  
Partial Pressure ◽  
Gas Flow ◽  
Loss Rate ◽  
Gas Temperature ◽  
Weight Loss Rate ◽  
Combustion Gas ◽  
Vapor Partial Pressure ◽  
Water Vapor Partial Pressure

In order to understand recession behavior and the amount of recession of Lu2Si2O7 in the combustion gas flow, sintered Lu2Si2O7 specimens were manufactured by hot pressing and exposed under various combustion gas flow conditions (T = 1300–1500 °C, P = 0.3 MPa, V = 150 m/s, PH2O = 27–69 kPa, t = 10h). After the exposure tests, etch pits, which are assumed to form due to volatilization of SiO2 in the grain boundary phase, were observed at the surface of specimen. The amount of Lu2SiO5 phase at the surface of specimen increased with the increase of gas temperature or water vapor partial pressure. A corresponding decrease in the amount of Lu2Si2O7 phase was observed. Furthermore, by using the average weight loss rate for exposure times of ten hours, the influence of gas temperature and water vapor partial pressure on weight loss rate was examined, and the amount of recession under gas turbine conditions was calculated.

scholarly journals Lipase mediated synthesis of polycaprolactone and its silica nanohybrid

2019 ◽  
Vol 91 (6) ◽  
pp. 957-965
Author(s):  
Meltem Akkulak ◽  
Yasemin Kaptan ◽  
Yasar Andelib Aydin ◽  
Yuksel Avcibasi Guvenilir
Keyword(s):  
Average Molecular Weight ◽  
Proton Nuclear Magnetic Resonance ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Structural Investigations ◽  
Crystallinity Degree ◽  
Molecular Weights ◽  
H Nmr

Abstract In this study, rice husk ash (RHA) silanized with 3-glycidyloxypropyl trimethoxysilane was used as support material to immobilize Candida antarctica lipase B. The developed biocatalyst was then utilized in the ring opening polymerization (ROP) of ε-caprolactone and in situ development of PCL/Silica nanohybrid. The silanization degree of RHA was determined as 4 % (w) by thermal gravimetric analysis (TGA). Structural investigations and calculation of molecular weights of nanohybrids were realized by proton nuclear magnetic resonance (1H NMR). Crystallinity was determined by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Scanning Electron Microscopy (SEM) was used for morphological observations. Accordingly, the PCL composition in the nanohybrid was determined as 4 %, approximately. Short chained amorphous PCL was synthesized with a number average molecular weight of 4400 g/mol and crystallinity degree of 23 %. In regards to these properties, synthesized PCL/RHA composite can find use biomedical applications.

Curing Reaction and Kinetic Parameters of Diallyl Orthophthalate Resin with Initiator Dicumyl Peroxide

2010 ◽  
Vol 160-162 ◽  
pp. 1366-1371
Author(s):  
Xiao Qin Yue ◽  
Qi Lin Mei ◽  
Zhi Xiong Huang ◽  
Peng Wen ◽  
Ling Huang
Keyword(s):  
Kinetic Parameters ◽  
Frequency Factor ◽  
Treatment Temperature ◽  
Curing Temperature ◽  
Dicumyl Peroxide ◽  
Scanning Calorimetry ◽  
Thermal Treatment Temperature ◽  
Reaction Heat ◽  
Curing Reaction ◽  
Gel Temperature

The curing reaction of diallyl orthophthalate(DAOP) resin, which was initiated by dicumyl peroxide(DCP), was studied by Fourier transform infrared spectroscopy(FTIR). Differential scanning calorimetry(DSC) was used to determine the curing behavior and kinetic parameters of dicumyl peroxide (DCP) / diallyl orthophthalate (DAOP) system. The results clarified that the curing reaction of DAOP resin could be initiated by DCP at 150-180°C and the reaction heat diffused slowly in curing process. The gel-temperature, curing temperature and thermal treatment temperature of the DCP(3%)/DAOP system were 145.46°C, 166.03°C and 173.83°C. The apparent activation energy, frequency factor and reaction order were 130.200kJ/mol, 5.231×1010 and 0.9455, respectively.

Aging Mechanism of Dam Concrete under the Action of Freeze-Thaw Damage

2014 ◽  
Vol 584-586 ◽  
pp. 2121-2124
Author(s):  
Yan Shi ◽  
Hua Quan Yang ◽  
Xiang Li ◽  
Jia Zheng Li
Keyword(s):  
Weight Loss ◽  
Elastic Modulus ◽  
Concrete Structure ◽  
Loss Rate ◽  
Hydration Products ◽  
Weight Loss Rate ◽  
Freeze Thaw ◽  
Aging Mechanism ◽  
Dam Concrete ◽  
Air Entrained Concrete

Aging mechanism of dam concrete under the action of freeze-thaw damage was analyzed by testing macro and micro performance. The results show that compressive, splitting tensile and flexural strengths reached 58.4%, 61.3% and 57.8% of the initial values after 150 cycles. Strength is the most sensitive indicator of freeze-thaw damage, followed by weight loss rate, relative dynamic elastic modulus and ultrasonic velocity. After freeze-thaw damage, concrete structure becomes loose, porous amount gradually increased and pore size especially over 25nm expanded. Microcracks not only exist in the hydration products, but also destroy the bubbles structure in air entrained concrete, which is the main cause of freeze-thaw damage.

Effects of Catalysts on Pyrolysis of Chlorella

2012 ◽  
Vol 433-440 ◽  
pp. 161-165
Author(s):  
Gui Ju Li ◽  
Ru Yu Zhao ◽  
Li Ping Bai
Keyword(s):  
Weight Loss ◽  
Loss Rate ◽  
Inorganic Compounds ◽  
Optimal Dosage ◽  
Maximum Weight ◽  
Weight Loss Rate ◽  
Two Factors ◽  
Catalytic Effects ◽  
Derivative Thermogravimetry ◽  
Maximum Weight Loss

Sodium compounds, Na2CO3，Na2SO4，NaCl, have been investigated with regard to their catalytic effects on chlorella pyrolysis by thermal analysis experiments. The influence of catalyst categories and dosage on chlorella pyrolysis were studied by the comparison and analysis of the TG（thermogravimetry）and DTG(derivative thermogravimetry) curves derived from tests of differential thermal balance of untreated chlorelal and chlorella mixed with three inorganic compounds of certain scale.The results show that the catalytic effect of the sodium compounds follow Na2CO3>Na2SO4>NaCl, Catalysts of Na2SO4，NaCl decreased the maximum weight loss rates while Na2CO3 increased them. And all the three additives lowered the pyrolysis temperature of chlorella，of which Na2CO3 made the highest conversion of chlorella pyrolysis. As the dosage of carbonate increased, the pyrolysis temperatures decreases and the maximum weight loss rate increases, but the conversion rate of chlorella pyrolysis decreases, considering these two factors, 5%wt is chosen as the optimal dosage of the catalysts.

Experimental Study on the Effect of Ultrasonic Cavitation on Pyrolysis Characteristics of Oil Shale

2013 ◽  
Vol 295-298 ◽  
pp. 3117-3123
Author(s):  
Hong Tian ◽  
Zheng Zhu Liao
Keyword(s):  
Weight Loss ◽  
Particle Size ◽  
Organic Matter ◽  
Oil Shale ◽  
Loss Rate ◽  
Ultrasonic Cavitation ◽  
Ultrasonic Frequency ◽  
Ultrasonic Power ◽  
Weight Loss Rate ◽  
Peak Value

In order to investigate the pyrolysis characteristics of oil shale under in the extreme conditions of high temperature and high pressure generated by the ultrasonic cavitation. The different particle size of oil shale is mixed with water in accordance with the volume ratio of 1:12, under in different ultrasonic frequency and different power, the ultrasonic radiation experiments and the thermogravimetric experiments of different samples have been done. The results show that the organic content of oil shale samples reduced after ultrasonic radiation, and the chemical reaction rate of the remaining organic matter become faster, and its reflected as the volatile separate out rate was accelerated and the changes of TG(Thermogravimetry) and DTG(Derivative Thermogravimetry) curves were steeper. Oil shale pyrolysis weight loss rate peak values and the organic matter decomposed percentage during the pyrolysis have the selective on the ultrasonic frequency, ultrasonic power and particle size of the oil shale. Oil shale pyrolysis weight loss rate peak value increased with decreasing of ultrasonic power, and the weight loss rate peak value corresponding to the peak temperature was increased with the increasing of ultrasonic frequency, and the weight loss rate peak value corresponding temperature decreased with particle size increasing of oil shale. We can draw the conclusion that the ultrasonic cavitation can decomposition organic matter of oil shale, then, we should in-depth research the ultrasonic refining shale oil.

scholarly journals Nondestructive Detection of Weight Loss Rate, Surface Color, Vitamin C Content, and Firmness in Mini-Chinese Cabbage with Nanopackaging by Fourier Transform-Near Infrared Spectroscopy

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2309
Author(s):  
Qiang Liu ◽  
Shaoxia Chen ◽  
Dandan Zhou ◽  
Chao Ding ◽  
Jiahong Wang ◽  
...  
Keyword(s):  
Weight Loss ◽  
Fourier Transform ◽  
Chinese Cabbage ◽  
Loss Rate ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Prediction Performance ◽  
Surface Color ◽  
Weight Loss Rate ◽  
Plsr Model

A nondestructive optical method is described for the quality assessment of mini-Chinese cabbage with nanopackaging during its storage, using Fourier transform-near infrared (FT-NIR) spectroscopy. The sample quality attributes measured included weight loss rate, surface color index, vitamin C content, and firmness. The level of freshness of the mini-Chinese cabbage during storage was divided into three categories. Partial least squares regression (PLSR) and the least squares support vector machine were applied to spectral datasets in order to develop prediction models for each quality attribute. For a comparative analysis of performance, the five preprocessing methods applied were standard normal variable (SNV), first derivative (lst), second derivative (2nd), multiplicative scattering correction (MSC), and auto scale. The SNV-PLSR model exhibited the best prediction performance for weight loss rate (Rp2 = 0.96, RMSEP = 1.432%). The 1st-PLSR model showed the best prediction performance for L* value (Rp2 = 0.89, RMSEP = 3.25 mg/100 g), but also the lowest accuracy for firmness (Rp2 = 0.60, RMSEP = 2.453). The best classification model was able to predict freshness levels with 88.8% accuracy in mini-Chinese cabbage by supported vector classification (SVC). This study illustrates that the spectral profile obtained by FT-NIR spectroscopy could potentially be implemented for integral assessments of the internal and external quality attributes of mini-Chinese cabbage with nanopacking during storage.

scholarly journals Laser Cladding and Anti-Laser Ablative Behaviour of Si-SiC-MoSi2-ZrB2 Composite Coatings on Carbon Surface

2020 ◽  
Author(s):  
Qixuan Wang ◽  
Yi Zhuo ◽  
Wenhao Wang ◽  
Litong Guo ◽  
Xueyu Tao ◽  
...  
Keyword(s):  
Weight Loss ◽  
Laser Ablation ◽  
Oxide Layer ◽  
Laser Cladding ◽  
Bonding Strength ◽  
Loss Rate ◽  
Composite Coatings ◽  
Carbon Surface ◽  
Weight Loss Rate ◽  
Coating Surface

Abstract A Si-SiC-MoSi2-ZrB2 antioxidation composite coating was fabricated by laser cladding technology on the graphite matrix surface, and laser ablation was carried out on the coating surface to evaluate the anti-ablation capability of the coating surface. The phase transformation, microstructure reconstruction and the change of binding strength between the coating and the matrix during the laser cladding and ablation were investigated. The coating of Si-SiC-MoSi2 series modified by 40wt% ZrB2 had the lowest weight loss rate and the highest coating bonding strength. The oxide mostly existed in amorphous form after laser cladding, and the semi-melting particles in laser path lap zone on the coating surface disappeared. The oxide layer peeled off and Mo-Zr-Si-O composite glass phase was formed on the coating surface. The internal microstructure of the coating co-existed with non-oriented fine needle-like dendrites and irregular particles, which improved the coating strength. After laser ablation, the coating modified by 40wt% ZrB2 had lower weight loss rate and higher scratch bonding strength compared with the unmodified coating of Si-SiC-MoSi2 series, which indicated that the ablation resistance of the coating was improved by the formation of continuous oxide layer on the surface.

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