scholarly journals Microwave-assisted synthesis of the lipase-catalyzed ring-opening copolymerization of ε-caprolactone and ω-pentadecanolactone: Thermal and FTIR characterization

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 651-658
Author(s):  
Wilberth A. Herrera-Kao ◽  
Manuel J. Aguilar-Vega ◽  
José Manuel Cervantes-Uc
Keyword(s):  
Ring Opening ◽  
Microwave Assisted Synthesis ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Intense Band ◽  
Microwave Assisted ◽  
Degradation Temperature ◽  
Ftir Characterization ◽  
Methylene Groups ◽  
Thermal Stability Of

AbstractMicrowave-assisted synthesis of the lipase-catalyzed ring opening polymerization of ε-caprolactone (ε-CL) and ω-pentadecanolactone (ω-PDL) monomers was studied. A series of P(CL-co-PDL), with different molar feed ratios, including (ε-CL/ω-PDL) 100/0, 75/25, 50/50, 25/75, and 0/100, were synthesized. The resulting polyesters were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The microwave-assisted polymerization of the monomers reached high conversions (91–95%) within 60 min. FTIR spectra showed the typical absorption bands of these polyesters. A very intense band in the carbonyl region, which was shifted from 1,720 cm−1 for PCL to 1,732 cm−1 for PPDL homopolymer, as well as peaks owing to methylene groups in the 2,990–2,850 cm−1 range. DSC results revealed that all polyester samples were semi-crystalline. Interestingly, the copolymers exhibited only one melting peak (Tm), and their Tm values linearly increased from 57°C to 95°C as PPDL concentration was increased. Thermal stability of polyesters also depended on PDL content; an increase in PDL concentration increases polymer degradation temperature (Td).

Preparation and Properties of Polybenzoxazine/Lignin Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 571-577 ◽  
Author(s):  
H.M. Emranul Haque ◽  
Zahidul Islam ◽  
Takehiro Kawauchi ◽  
Tsutomu Takeichi
Keyword(s):  
Thermal Stability ◽  
Ring Opening ◽  
Lignin Content ◽  
Weight Ratio ◽  
Alloy Film ◽  
Ring Opening Polymerization ◽  
Scanning Calorimetry ◽  
Alloy Films ◽  
Degradation Temperature ◽  
Thermal Stability Of

Polymer alloys of polybenzoxazine and lignin were prepared by mixing benzoxazine and lignin, followed by curing. The ring-opening polymerization of benzoxazine in the presence of lignin was investigated by differential scanning calorimetry. It was found that lignin accelerates the ring-opening polymerization of benzoxazine. Polybenzoxazine/lignin alloy films were prepared by varying the weight ratio of benzoxazine and lignin. Transparent alloy film was obtained up to 2 wt. % content of lignin, but phase separation was observed at higher content of lignin. Thermal stability of the alloy films was examined by thermogravimetric analysis from 40 °C to 850 °C. The alloy film with 10 wt. % lignin showed highest onset of degradation temperature. Moreover, char yield of alloy films was increased with increasing the lignin content, suggesting higher flame retardancy of the alloy films than the pristine polybenzoxazine.

Microwave-assisted ring-opening polymerization of poly (glycolic acid-co-lactic acid) copolymers

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Guang Li ◽  
Na Zhao ◽  
Wei Bai ◽  
Dong Liang Chen ◽  
Cheng Dong Xiong
Keyword(s):  
Lactic Acid ◽  
Ring Opening ◽  
Glycolic Acid ◽  
Raw Materials ◽  
Irradiation Time ◽  
Ring Opening Polymerization ◽  
Feed Ratio ◽  
Microwave Assisted Synthesis ◽  
Component Ratio ◽  
Microwave Assisted

AbstractThe microwave-assisted synthesis of poly(glycolic acid-co-lactic acid) (PGLA) copolymers by ring-opening polymerization of glycolide (GA) and L-lactide (L-LA) was studied. The microwave irradiation time and feed ratios on the molecular weights, as well as the thermal properties of the copolymers were discussed. These copolymers were characterized by 1H-NMR, GPC and DSC. It was found that the largest molecular weight ([η]: 0.8745 dL/g) of PGLA5050 was obtained at the irradiation time of 5 min. The color of the copolymers changed from white to light brown, and the yield was higher with the extension of the irradiation time. The molar component ratio of GA in PGLA (FG) was higher than the initial GA feed ratio (nGA) in the raw materials. As the nGA content increased, the glass transition temperature (Tg) of the copolymers decreased and the melting temperature (Tm) of the copolymers increased.

Melt Intercalation of PMMA into Organically-Modified Layered Silicate

1999 ◽  
Vol 576 ◽  
Author(s):  
Z. Shen ◽  
G. P. Simon ◽  
Y-B. Cheng
Keyword(s):  
Large Scale ◽  
Weight Ratio ◽  
Layered Silicate ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Melt Intercalation ◽  
Degradation Temperature ◽  
Organically Modified

ABSTRACTOrganic-inorganic hybrid nanocomposite materials of poly(methyl methacrylate) (PMMA) and organically-modified silicate (B34) systems have been prepared via melt intercalation with variation of tacticity and molecular weight as the main molecular variables. Only two of the PMMA samples (with the lowest glass transition temperatures) were able to undergo large-scale intercalation into B34, as seen by X-ray diffraction (XRD) and Infrared spectroscopy. The saturation weight ratio of PMMA to B34 was about 25:75 (wt%), deduced by a controlled differential scanning calorimetry (DSC) experiment. Two new absorption bands of PMMA-B34 hybrid in Fourier transform-infrared spectrometry (FTIR) were demonstrated for first time in this system and show a change in molecular interaction of bulk and intercalated PMMA. The degradation temperature of the PMMA-B34 hybrid is higher than that of PMMA alone, or a physical mixture of PMMA and silicate under an air or a nitrogen flow.

GUM KARAYA-G-POLY (ACRYLAMIDE): MICROWAVE ASSISTED SYNTHESIS, OPTIMISATION AND CHARACTERISATION

2020 ◽  
pp. 143-152
Author(s):  
LOVELEENPREET KAUR ◽  
G. D. GUPTA
Keyword(s):  
Ammonium Nitrate ◽  
Irradiation Time ◽  
Ceric Ammonium Nitrate ◽  
Microwave Assisted Synthesis ◽  
Scanning Calorimetry ◽  
Box Behnken Design ◽  
Grafting Efficiency ◽  
Microwave Assisted ◽  
Gum Karaya ◽  
Karaya Gum

Objective: The objective of the present research is to formulate acrylamide grafted Karaya gum by using microwave-assisted grafting method and optimisation is performed by using Box behnken design. Methods: The extracted mucilage of gum Karaya was modified into grafted gum Karaya by using a microwave-assisted method. Acrylamide was used as monomer and ceric ammonium nitrate (CAN) is used as redox initiator. The experimental design for optimisation include three independent variables gum concentration (X1), ceric ammonium nitrate (CAN) amount (X2) and irradiation time (X3) while the dependent variables were % yield (Y1), % grafting (Y2) and % grafting efficiency (Y3). The optimised formulation was characterized by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), x-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Results: After optimisation the formulation with acrylamide amount 5 g, ceric ammonium nitrate amount 200 mg and irradiation time of 2 min was selected as optimized formulation. The optimised formulation has percentage grafting of 853.5%, with grafting efficiency of 77.59%. Conclusion: The application of box behnken design for optimisation was performed successfully in microwave assisted grafting of acrylamide on karaya gum.

Microwave-assisted synthesis of glycopolymers by ring-opening metathesis polymerization (ROMP) in an emulsion system

2017 ◽  
Vol 8 (44) ◽  
pp. 6709-6719 ◽  
Author(s):  
Fei Fan ◽  
Chao Cai ◽  
Lei Gao ◽  
Jun Li ◽  
Ping Zhang ◽  
...  
Keyword(s):  
Emulsion Polymerization ◽  
Ring Opening ◽  
Microwave Assisted Synthesis ◽  
Emulsion System ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
Microwave Assisted ◽  
System P

Well-defined glycopolymers fabricated by microwave-accelerated emulsion polymerization offer promising prospects for deciphering glycan-dependent interactions.

scholarly journals Gum colocasia-g-polyacrylamide: Microwave-assisted synthesis and characterization

2020 ◽  
Vol 11 (4) ◽  
pp. 6698-6706
Author(s):  
Loveleenpreet Kaur ◽  
Gupta G D
Keyword(s):  
Irradiation Time ◽  
Colocasia Esculenta ◽  
Microwave Assisted Synthesis ◽  
Scanning Calorimetry ◽  
Grafting Efficiency ◽  
Microwave Assisted ◽  
Graft Polymers ◽  
Percentage Yield ◽  
Effect On Yield ◽  
Microwave Time

In the present investigation, an attempt has been made for grafting of acrylamide on the backbone of Colocasia esculenta by using microwave-assisted grafting method, which is a convenient and versatile route for the development of polysaccharide-based materials. The dried mucilage of colocasia was prepared from fresh rhizomes. The optimization was performed by using Box Behnken matrix design (BBD) and response surface methodology (RSM) using design expert software. A series of graft polymers, varying in the amount of acrylamide, ammonium persulphate and microwave irradiation was prepared. The effect of Microwave time, gum concentration and power on percentage yield, percentage grafting and percentage grafting efficiency has been optimized and evaluated by 3D surface response graphs. It has been observed that power and irradiation time has a significant synergistic effect on % yield, % grafting and % grafting efficiency however gum concentration produce slight increment up to a limit after that the effect becomes almost constant. The selected optimized formulation is F8  with a percentage yield of 99.57%, percentage grafting of 634.33% and percentage grafting efficiency of 87.49%. Optimized formulation was subjected to Fourier transform infrared spectroscopy, Differential scanning calorimetry, X-ray diffraction and Scanning electron microscopy for characterization which committed the grafting of acrylamide on Colocasia esculenta.

scholarly journals Microwave-Assisted Synthesis of Polylactic Acid-Diol for Polyurethane as Biodegradable Packaging Material

2021 ◽  
Vol 1192 (1) ◽  
pp. 012015
Author(s):  
N I M Razali ◽  
F Ali ◽  
A S Azmi ◽  
T N M T Ismail ◽  
M E S Mirghani ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Human Life ◽  
Gel Permeation Chromatography ◽  
Hydroxyl Group ◽  
Synthesis Process ◽  
Microwave Assisted Synthesis ◽  
Aquatic Life ◽  
Daily Lives ◽  
Microwave Assisted ◽  
Ftir Characterization

Abstract Since its discovery, plastic has been a part of human life and is widely employed in our daily lives. Excessive use of plastic has raised pollution rates around the world, with plastic ending up in landfills or the sea, posing a threat to both terrestrial and aquatic life. Considering this problem, the widespread use of polyurethanes (PUs) in many industries has resulted in unavoidable PUs pollution in everyday life. A reaction involving prepolymer, isocyanate, and polyol can be used to make PUs. Petroleum-based polyol and vegetable oil-based polyol are the two types of polyols available. Isocyanate will become the hard domain of the polymer in the PUs polymer chain, while polyol will become the soft domain. Polylactic acid-diol is the prepolymer used to make PU (PLA-diol). PLA-diol was previously made using a traditional heating approach, which takes a long time. To overcome this traditional method, microwave-assisted synthesis is proposed to synthesize the PLA-diol. The synthesis process involved synthesizing PLA-diol at different microwave power (450W – 900W) and at different reaction time (1 hour – 2 hours). The peak of hydroxyl group in synthesized PLA-diol was characterized via the Fourier Transform Infrared Spectroscopy (FTIR) characterization to determine the functional groups of PLA-diol and gel permeation chromatography (GPC) characterization was done to determine the molecular weight of PLA-diol. The resulting PLA-diol will then be used to synthesis biodegradable PUs in the subsequence study.

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