Investigation of the effect of some variables on terpolymerization process of vinyl monomers in CSTR by design of experimental method

e-Polymers ◽  
2018 ◽  
Vol 18 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Amin Moslemi ◽  
Rouhallah Bagheri ◽  
Negar Karami ◽  
Ehsan Mokhtari
Keyword(s):  
Intrinsic Viscosity ◽  
Monomer Conversion ◽  
Monomer Mixture ◽  
Continuous Stirred Tank Reactor ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mixture Ratio ◽  
Redox Initiator ◽  
Initiator System

AbstractAqueous slurry free radical terpolymerization of acrylonitrile (AN) with vinyl acetate (VAc) and a constant amount of 2-acrylamido-2-methylpropane sulfunic acid (AMPS) using K2S2O8/NaHSO3 redox initiator was carried out in a 15-l continuous stirred tank reactor at constant temperature (60°C) and atmospheric pressure. A three-level response surface method based on central composite design was applied to investigate the effect of VAc concentration (wt%) in monomer mixture, bisulfite- to-persulfate ratio in redox initiator system $\left( {\frac{{{\text{[HSO}}_3^ - ]}}{{[{{\text{S}}_2}{\text{O}}_8^{ - 2}]}}} \right)$ and bisulfite-to-monomer mixture ratio $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{{\text{AN}} + {\text{VAc}}}}} \right)$ on the monomer conversion percentage to polymer, intrinsic viscosity [(η)] and sulfur end groups (SEG) index of the prepared polymers. Experimental results showed that the optimum conditions for synthesis of AN-VAc-AMPS system can be addressed as VAc=9 wt%, $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{[{{\text{S}}_2}{\text{O}}_8^{ - 2}]}}} \right) = 9.6$ and $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{{\text{AN}} + {\text{VAc}}}}} \right) = 0.027.$ Monomer conversion percentage to polymer, intrinsic viscosity and SEG index under optimum conditions were 75%, 1.38 dl/g and 190, respectively. The synthesized polymer under these optimum conditions can satisfy the requirements for acrylic fiber production in which its characterization was confirmed with Fourier transform infrared spectroscopy, nuclear magnetic resonance, elemental analysis, X-ray diffraction, differential scanning calorimetry and scanning electron microscope.

scholarly journals Ultrasonic Pretreatment in Synthesis of Caprylic-Rich Structured Lipids by Lipase-Catalyzed Acidolysis of Corn Oil in Organic System and Its Physicochemical Properties

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 566 ◽  
Author(s):  
Chonghui Yue ◽  
Hongyan Ben ◽  
Junwen Wang ◽  
Tiantian Li ◽  
Guoping Yu
Keyword(s):  
Physicochemical Properties ◽  
Corn Oil ◽  
Structured Lipids ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Organic System ◽  
Ultrasonic Pretreatment ◽  
Pretreatment Time ◽  
Chain Type

The current work was to evaluate the lipase-catalyzed acidolysis of corn oil with caprylic acid (CA) in organic system under bath ultrasonic pretreatment and to analyze the physicochemical properties of structured lipids (SLs). Under optimum conditions (Novozym 40086 lipase, 200 W ultrasound power, 10 min ultrasound pretreatment time, 12% dosage of lipase, Triacylglycerol (TAG)/Free fatty acids (FFA): 1/8, 40 °C for 6 h), a 45.55% CA incorporation was obtained (named SLs-U). The highest CA incorporation was 32.75% for conventional method at reaction time of 10 h (named SLs-N). The predominant TAG types of SLs were MLM (medium-, long- and medium-chain-type TAGs) and MLL (medium-, long- and long-chain-type TAGs). X-ray diffraction analysis revealed that both SLs-U and SLs-N present β form. Differential scanning calorimetry (DSC) analysis showed that both SLs-U and SLs-N show a lower melting and crystallization temperature than corn oil. This study suggested that bath ultrasonic pretreatment can accelerate lipase-catalyzed acidolysis synthesis of MLM structured lipids in an organic system, and two kinds of structured lipids show similar physicochemical properties.

scholarly journals Physical Mixture Interaction of Acetaminophenol with Naringenin

2018 ◽  
Vol 18 (1) ◽  
pp. 18 ◽  
Author(s):  
Normyzatul Akmal Abd Malek ◽  
Hamizah Mohd Zaki ◽  
Mohammad Noor Jalil
Keyword(s):  
Interaction Strength ◽  
Active Pharmaceutical Ingredient ◽  
Binary Interaction ◽  
Molar Ratio ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mixture Ratio ◽  
X Ray ◽  
New Phase

The interaction of Active Pharmaceutical Ingredient (API) with other compounds will affect drugs stability, toxicity, modified dissolution profiles or may form a new compound with the different crystal structure. Acetaminophenol (APAP), the most common drug used widely (also known as Panadol) was mixed with Naringenin (NR) to glance for a new phase of interactions leading to new compound phase. The amide-acid supramolecular heterosynthon; N-H…O interaction between acid and the respective base were observed in the APAP-NR mixture blends. The interaction was prepared by the binary interaction from neat grinding and liquid-assisted grinding techniques at a different stoichiometry of binary mixture ratio of APAP-NR which were 1:1, 1:2 and 2:1 molar ratio. The interaction was estimated using Group Contribution Method (GCM) and physicochemical properties were characterized by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), powder X-ray diffraction (PXRD) and Differential Scanning Calorimetry (DSC) analysis. The GCM calculation gave good interaction strength at 212.93 MPa1/2. The ATR-FTIR, DSC and PXRD results obtained revealed an interaction with new phase formed.

Studies of Natural Rubber Grafted with Acrylic Monomers

2010 ◽  
Vol 123-125 ◽  
pp. 1263-1266
Author(s):  
Suek Songprateepkul ◽  
Pranee Chumsamrong
Keyword(s):  
Natural Rubber ◽  
Graft Copolymerization ◽  
Monomer Conversion ◽  
Monomer Mixture ◽  
Nmr Spectrum ◽  
Grafting Efficiency ◽  
Weight Percentage ◽  
Grafting Reaction ◽  
Redox Initiator ◽  
Percentage Conversion

In order to increase polarity and widen application of natural rubber, the natural rubber (NR) was modified by graft copolymerization with methyl methacrylate (MMA) and glycidyl methacrylate (GMA). The grafting reaction was carried out using emulsion polymerization at 40°C. Redox initiator was used to initiate polymerization. Weight percentage ratio of MMA to GMA was firstly fixed at 90/10 in order to study the effects of amount of initiator and monomer mixture-to-rubber ratio on grafting efficiency [GE(%)] and percentage conversion of monomer (%conversion). The graft copolymerization condition that showed the highest grafting efficiency was chosen to study the effect of MMA-to-GMA ratio. It was found that the highest grafting efficiency [GE(%) = 85.11] were obtained when 1 part of NR, 0.75 part of monomer mixture and 1 phr of initiator were used. 1H-NMR spectrum of the graft copolymer with grafting efficiency of 85.11% illustrated that main monomer grafted onto NR chain was MMA. However, there was a signal of GMA that attached onto the NR chain. The results from an adjustment of MMA-to-GMA ratio showed that grafting efficiency tended to decrease with increasing the amount of GMA. On the other hand, an adjustment of MMA-to-GMA ratio did not significantly affect %conversion.

A Novel Eco-Friendly Scale and Corrosion Inhibitor Modified by β-Cyclodextrin

2017 ◽  
Vol 70 (8) ◽  
pp. 933 ◽  
Author(s):  
Mingjin Tang ◽  
Jianbo Li ◽  
Zhengrong Ye ◽  
Zimin Kou ◽  
Luoping Fu
Keyword(s):  
Corrosion Inhibition ◽  
Inhibition Efficiency ◽  
Saline Water ◽  
Gel Permeation Chromatography ◽  
X Ray Diffraction ◽  
Flight Mass Spectrometry ◽  
Scale Inhibition ◽  
Redox Initiator ◽  
Initiator System ◽  
Inhibition Performance

A polymer, β-MEA, was synthesised from β-cyclodextrin (β-CD), 3-chloro-2-methylpropene (MAC), epoxysuccinic acid (ESA), and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) with a (NH4)2S2O8-NaHSO3 redox initiator system by aqueous solution radical polymerisation. β-MEA was characterised by means of IR spectroscopy, time-of-flight mass spectrometry, gel permeation chromatography, and thermogravimetric analysis. Its structure, molecular weight, thermal stability, scale and corrosion inhibition performance and mechanism were investigated. The results verified that β-MEA achieves a better scale inhibition efficiency for BaSO4 compared with poly(aspartic acid) (PASP) (100 % cf. 94.9 % at a concentration of 20 mg L−1) and a better corrosion inhibition efficiency of N80 carbon steel in saline water compared with PESA (91.2 % cf. 79.7 % at a concentration of 1 g L−1). The BaSO4 was characterised by scanning electron microscopy (SEM) and X-ray diffraction to investigate the crystal morphology of the scale. Primary research on the mechanism for corrosion inhibition was carried by SEM-chemical analysis.

Experimental study on texturability of filament yarns produced from recycled PET

2020 ◽  
Vol 90 (23-24) ◽  
pp. 2703-2713
Author(s):  
Marjan Abbasi ◽  
Mohammad Reza Mohades Mojtahedi ◽  
Richard Kotek
Keyword(s):  
Experimental Study ◽  
Differential Scanning Calorimetry ◽  
Polyethylene Terephthalate ◽  
Intrinsic Viscosity ◽  
Similar Response ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Recycled Pet ◽  
Elongation At Break ◽  
X Ray

In the present work, the texturability of filament yarns produced from recycled bottle grade polyethylene terephthalate (R-PET) and new fiber grade PET (FG-PET) were investigated and compared experimentally. Yarn spun on a spin-draw spinning machine was draw-textured. Elongation at break in each fiber was set to reach 30 ± 5% in the texturing machine. The effect of the draw-texturing conditions on thermomechanical, structural, and crimp properties were examined. Draw-texturing behaviors of the fibers were analyzed using differential scanning calorimetry and measurements of intrinsic viscosity, mechanical and crimp properties, density, and X-ray diffraction. The results indicate that crystallinity of the textured yarn from R- PET and FG-PET has increased compared to the semi-drawn yarns. Further, the lateral dimensions of the R-PET crystals are relatively well developed. Crimp properties show nearly similar response for two polymer yarns for the texturing process. It was found that R-PET can be the premier feed supply for the draw-texturing process and that filaments with appropriate confidence could be obtained from the R-PET.

Glibenclamide-Nicotinamide Cocrystals Synthesized by The Solvent Evaporation Method to Enhance Solubility and Dissolution Rate of Glibenclamide

2019 ◽  
Vol 9 (01) ◽  
pp. 21-26
Author(s):  
Arif Budiman ◽  
Ayu Apriliani ◽  
Tazyinul Qoriah ◽  
Sandra Megantara
Keyword(s):  
Solvent Evaporation ◽  
Physical Mixture ◽  
Dissolution Profile ◽  
Solvent Evaporation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Evaporation Method ◽  
Dissolution Properties ◽  
Mixture Characterization

Purpose: To develop glibenclamide-nicotinamide cocrystals with the solvent evaporation method and evaluate their solubility and dissolution properties. Methods: Cocrystals of glibenclamide-nicotinamide (1:2) were prepared with the solvent evaporation method. The prediction of interactive cocrystals was observed using in silico method. The solubility and dissolution were performed as evaluation of cocrystals. The cocrystals also were characterized by differential scanning calorimetry (DSC), infrared spectrophotometry, and powder X-ray diffraction (PXRD). Result: The solubility and dissolution profile of glibenclamide-nicotinamide cocrystal (1:2) increased significantly compared to pure glibenclamide as well as its physical mixture. Characterization of cocrystal glibenclamide-nicotinamide (1:2) including infrared Fourier transform, DSC, and PXRD, indicated the formation of a new solid crystal phase differing from glibenclamide and nicotinamide. Conclusion: The confirmation of cocrystal glibenclamide-nicotinamide (1:2) indicated the formation of new solid crystalline phases that differ from pure glibenclamide and its physical mixture

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

scholarly journals Characterization of Beeswax, Candelilla Wax and Paraffin Wax for Coating Cheeses

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 261
Author(s):  
Adolfo Bucio ◽  
Rosario Moreno-Tovar ◽  
Lauro Bucio ◽  
Jessica Espinosa-Dávila ◽  
Francisco Anguebes-Franceschi
Keyword(s):  
Physical And Mechanical Properties ◽  
Tensile Tests ◽  
Paraffin Wax ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Dimensional Changes ◽  
Ductile Behavior ◽  
Candelilla Wax

A study on the physical and mechanical properties of beeswax (BW), candelilla wax (CW), paraffin wax (PW) and blends was carried out with the aim to evaluate their usefulness as coatings for cheeses. Waxes were analyzed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), permeability, viscosity, flexural and tensile tests and scanning electron microscopy. Cheeses were coated with the waxes and stored for 5 weeks at 30 °C. Measured parameters were weight, moisture, occurrence and degree of fractures, and dimensional changes. The crystal phases identified by XRD for the three waxes allowed them to determine the length of alkanes and the nonlinear compounds in crystallizable forms in waxes. FTIR spectra showed absorption bands between 1800 and 800 cm−1 related to carbonyls in BW and CW. In DSC, the onset of melting temperature was 45.5 °C for BW, and >54 °C for CW and PW. Cheeses coated with BW did not show cracks after storage. Cheeses coated with CW and PW showed microcraks, and lost weight, moisture and shrunk. In the flexural and tensile tests, BW was ductile; CW and PW were brittle. BW blends with CW or PW displays a semi ductile behavior. Cheeses coated with BW blends lost less than 5% weight during storage. The best waxes were BW and the blends.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

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