scholarly journals Prediction of the Miscibility of PBAT/PLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2339
Author(s):  
Shen Su
Keyword(s):  
Molecular Weight ◽  
Volume Fraction ◽  
Molecular Level ◽  
Average Molecular Weight ◽  
Cost Effective ◽  
Solubility Parameters ◽  
Molar Ratio ◽  
Cost Effective Approach ◽  
Group Contribution Methods ◽  
Prediction And Simulation

Designing polymer structures and polymer blends opens opportunities to improve the performance of plastics. Blending poly(butylene adipate-co-terephthalate) (PBAT) and polylactide (PLA) is a cost-effective approach to achieve a new sustainable material with complementary properties. This study aimed to predict the theoretical miscibility of PBAT/PLA blends at the molecular level. First, the basic properties and the structure of PBAT and PLA are introduced, respectively. Second, using the group contribution methods of van Krevelen and Hoy, the Hansen and Hildebrand solubility parameters of PBAT and PLA were calculated, and the effect of the molar ratio of the monomers in PBAT on the miscibility with PLA was predicted. Third, the dependence of the molecular weight on the blend miscibility was simulated using the solubility parameters and Flory–Huggins theory. Next, the glass transition temperature of miscible PBAT/PLA blends, estimated using the Fox equation, is shown graphically. According to the prediction and simulation, the blends with a number-average molecular weight of 30 kg/mol for each component were thermodynamically miscible at 296 K and 463 K with the possibility of spinodal decomposition at 296 K and 30% volume fraction of PBAT. This study contributes to the strategic synthesis of PBAT and the development of miscible PBAT/PLA blends.

Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

1995 ◽  
Vol 60 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Marta Pacovská ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Induction Period ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Polymer Yield ◽  
Positive Effect ◽  
Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

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.

Synthesis and Properties of Biodegradable ABA Triblock Copolymers of Polylactide (A) and Polyethylene Glycol (B)

2006 ◽  
Vol 11-12 ◽  
pp. 469-472 ◽  
Author(s):  
Shu Xian Shi ◽  
Yu Zheng Xia ◽  
Xiao Yan Ma ◽  
Shu Ke Jiao ◽  
Xiao Yu Li
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
Ring Opening ◽  
Average Molecular Weight ◽  
Analytical Techniques ◽  
Normal Pressure ◽  
Molar Ratio ◽  
Poly Ethylene Glycol ◽  
Molar Ratios ◽  
Poly Ethylene

The triblock ABA copolymers of poly (D,L-lactide)-b-poly (ethylene glycol)-b-poly (D,L-lactide) (PDLLA-PEG-PDLLA) were synthesized by bulk ring-opening polymerization in the presence of N2 under normal pressure, using the D,L-lactide (DLLA) as monomer, hydroxyl endgroups of poly(ethylene glycol) (PEG) as initiator and the stannous octoate as the catalyst. The resulting copolymers were characterized by various analytical techniques. Effects of molar ratios of lactide to PEG and the chain length of PEG on the viscosity-average molecular weight of the copolymers, the biodegradation behaviors and hydrophilicity of the copolymers were investigated in detail. The results showed that the viscosity-average molecular weight and the contact angle of the copolymers increased with the molar ratio of lactide to PEG, but water uptake and degradability decreased.

Binary molybdenum-based catalyst for coordination polymerization of styrene

2016 ◽  
Vol 49 (5) ◽  
pp. 408-421 ◽  
Author(s):  
Jieting Geng ◽  
Youguo Shao ◽  
Feng Song ◽  
Feng Li ◽  
Jing Hua
Keyword(s):  
Molecular Weight ◽  
Catalyst Activity ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Catalyst System ◽  
Bulk Polymerization ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Coordination Polymerization ◽  
Co Catalyst

Coordination polymerization of styrene (St) using molybdenum pentachloride supported by phosphite ligand in the presence of metal organic compound was studied for the first time. The types of phosphite and co-catalysts significantly affected the catalytic activity of the molybdenum (V) (Mo(V)) active center and the number-average molecular weight ( Mn) of the resultant polymer. Among the examined catalysts, tri(nonylphenyl)phosphite (TNPP) ligand and AlOPhCH3( i-Bu)2 as co-catalyst provided the polymer with highest yield (up to 87.1%), metallocene as co-catalyst provided the polymer with highest Mn (up to 5.32 × 105). The effect of [P]/[Mo] molar ratio on catalyst activity of the polymerization was discussed and the structures of Mo·TNPP complexes were preliminarily studied by infrared (IR) and ultraviolet spectroscopies. Besides, the polystyrene (PS) samples synthesized through bulk polymerization and solution polymerization were characterized by gel permeation chromatography, IR, carbon 13 nuclear magnetic resonance, and differential scanning calorimetry, respectively, and the results indicated both of the PS had high molecular weight (approximately 105) and atactic structure. All these results demonstrated that Mo(V) catalyst system was very effective for St polymerization.

Study on Synthesis and Properties of Phenols Polymer Syntan Catalyzed by Enzyme

2011 ◽  
Vol 138-139 ◽  
pp. 1072-1077
Author(s):  
Sheng Hua Lv ◽  
Rui Gong ◽  
Yan Fen Ma
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Structure And Properties ◽  
Monomer Composition ◽  
Gel Permeation

A phenolic copolymer was synthesized from resorcinol (RSC) and 3,5-dihydroxy benzoic acid (DBA) using horseradish peroxidase (HRP)/H2O2 as the radical copolymerization’s initiateor. It was discussed that the effects of monomer composition on the properties of the copolymer. The best molar ratio was 1:1. The structure and properties of the copolymer was characterized by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (HNMR), Molecular weight (MW) was determined by gel permeation chromatography (GPC). The result shows that the average molecular weight of the copolymer is about 40000. The effect of dosage of HRP on the properties of the copolymer was investigated. And the mechanism of polymerization of RSC and DBA was advanced. The copolymer was used as tanning agent, applied results show that it has excellent retanning properties. It was realized the applicatiom of HRP on the phenols syntan.

scholarly journals Extract Methods, Molecular Characteristics, and Bioactivities of Polysaccharide from Alfalfa (Medicago sativa L.)

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1181 ◽  
Author(s):  
Chen Zhang ◽  
Zemin Li ◽  
Chong-Yu Zhang ◽  
Mengmeng Li ◽  
Yunkyoung Lee ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Medicago Sativa ◽  
Biological Activities ◽  
Average Molecular Weight ◽  
Molar Ratio ◽  
Molecular Characteristics ◽  
Ionization Mass ◽  
Potential Candidate ◽  
Dependent Manner ◽  
Medicago Sativa L

The polysaccharide isolated from alfalfa was considered to be a kind of macromolecule with some biological activities; however, its molecular structure and effects on immune cells are still unclear. The objectives of this study were to explore the extraction and purifying methods of alfalfa (Medicago sativa L.) polysaccharide (APS) and decipher its composition and molecular characteristics, as well as its activation to lymphocytes. The crude polysaccharides isolated from alfalfa by water extraction and alcohol precipitation methods were purified by semipermeable membrane dialysis. Five batches of alfalfa samples were obtained from five farms (one composite sample per farm) and three replicates were conducted for each sample in determination. The results from ion chromatography (IC) analysis showed that the APS was composed of fucose, arabinose, galactose, glucose, xylose, mannose, galactose, galacturonic acid (GalA), and glucuronic acid (GlcA) with a molar ratio of 2.6:8.0:4.7:21.3:3.2:1.0:74.2:14.9. The weight-average molecular weight (Mw), number-average molecular weight (Mn), and Z-average molecular weight (Mz) of APS were calculated to be 3.30 × 106, 4.06 × 105, and 1.43 × 108 g/mol, respectively, according to the analysis by gel permeation chromatography-refractive index-multiangle laser light scattering (GPC-RI-MALS). The findings of electron ionization mass spectrometry (EI-MS) suggest that APS consists of seven linkage residues, namely 1,5-Araf, galactose (T-D-Glc), glucose (T-D-Gal), 1,4-Gal-Ac, 1,4-Glc, 1,6-Gal, and 1,3,4-GalA, with molar proportions of 10.30%, 4.02%, 10.28%, 52.29%, 17.02%, 3.52%, and 2.57%, respectively. Additionally, APS markedly increased B-cell proliferation and IgM secretion in a dose- and time-dependent manner but not the proliferation and cytokine (IL-2, -4, and IFN-γ) expression of T cells. Taken together, the present results suggest that APS are macromolecular polymers with a molar mass (indicated by Mw) of 3.3 × 106 g/mol and may be a potential candidate as an immunopotentiating pharmaceutical agent or functional food.

Ion Exchange Synthesis of Bi2MoO6/BiOI Heterojunctions for Photocatalytic Degradation and Photoelectrochemical Water Splitting

NANO ◽  
2016 ◽  
Vol 11 (08) ◽  
pp. 1650095 ◽  
Author(s):  
Linlin Fan ◽  
Bo Wei ◽  
Lingling Xu ◽  
Yang Liu ◽  
Wanlu Cao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Anion Exchange ◽  
Cost Effective ◽  
Molar Ratio ◽  
Radical Scavengers ◽  
Photoelectrochemical Performance ◽  
Exchange Method ◽  
Cost Effective Approach ◽  
Light Excitation ◽  
Photoelectrochemical Measurement

In this study, flower-like Bi2MoO6/BiOI heterostructure photocatalysts were synthesized via an anion exchange method using BiOI as precursor. The composition of Bi2MoO6/BiOI can be easily controlled by adjusting the MoO[Formula: see text]/I[Formula: see text] molar ratio. Photocatalytic activity studies based on the degradation of Rhodamine B (RhB) show that Bi2MoO6/BiOI[Formula: see text][Formula: see text][Formula: see text]50% photocatalyst exhibited the best performance under visible light excitation. The radical scavengers test demonstrated that holes was the main reactive species for the degradation of RhB, and[Formula: see text][Formula: see text][Formula: see text][Formula: see text]O[Formula: see text] also took part in the photodecomposition process. Photoelectrochemical measurement reveals that the Bi2MoO6/BiOI[Formula: see text][Formula: see text][Formula: see text]50% exhibit enhanced carrier densities, charge separation and photocurrent compared with the original Bi2MoO6 and BiOI. Our results show that bismuth-based heterojunctions fabricated through the anion exchange method could be a cost-effective approach to improve the photocatalytic activity and photoelectrochemical performance of BiOI.

Synthesis Star-Shaped Cationic Polyacrylamide- Dimethyl- Diallyl- Ammonium- Chloride by "Core-First" Method

2013 ◽  
Vol 634-638 ◽  
pp. 2049-2055 ◽  
Author(s):  
Jing Wang ◽  
Liang Chen ◽  
Huai Yuan Zhao ◽  
Jing Deng
Keyword(s):  
Molecular Weight ◽  
Ammonium Chloride ◽  
Average Molecular Weight ◽  
Star Polymer ◽  
Molar Ratio ◽  
Polymerization Temperature ◽  
Polymer Molecular Weight ◽  
Synthesis Mechanism ◽  
Linear Type ◽  
Cationic Polyacrylamide

A star-shaped cationic polyacrylamide(star-P(AM-DMDAAC)) was synthesized by free radical copolymerization of monomer of acrylamide(AM) and dimethyl diallyl ammonium chloride (DMDAAC) using the redox system of pentaerythritol(PETL) and (NH4)2S2O8 as initiator. And the factor influence the polymer molecular weight were detailed studied. The results indicate that the effects of polymerization temperature, the dosage of initiator, molar ratio of AM to DMDAAC have a greater influence on the viscosity-average molecular weight of the copolymer. and adding urea and ethylenediamine tetraacetic acid(EDTA) for additive and adding ammonia for adjustment the acidity of catalyst system can also increase the polymer molecular weight. The sludge dewatering performance of self-made star-P(AM-DMDAAC) is better than the commercial linear type cationic polyacrylamide flocculants in the market. The structures of the resulting products were characterized by nuclear magnetic resonance(1H-NMR), the PETL as "core" of the star polymer, the AM and DMDAAC as "arms" of the star polymer. And the synthesis mechanism was proposed in this paper.

CONSTITUTION OF THE HEMICELLULOSE FROM MESTA FIBER (HIBISCUS CANNABINUS)

1963 ◽  
Vol 41 (9) ◽  
pp. 2346-2350 ◽  
Author(s):  
S. K. Sen
Keyword(s):  
Molecular Weight ◽  
Uronic Acid ◽  
Average Molecular Weight ◽  
Analytical Data ◽  
Degree Of Polymerization ◽  
Hibiscus Cannabinus ◽  
Molar Ratio ◽  
Alkaline Solutions ◽  
Number Average Molecular Weight ◽  
Hydrolysis Of

The chlorite holocellulose of mesta fiber (Hibiscus cannabinus) was extracted with alkaline solutions of successively increasing concentration and finally with alkaline borate solution. Hemicellulose fractions (I–IV) were thus obtained. Analytical data are recorded for each fraction.Partial acid hydrolysis of the mesta hemicellulose gave 2-O-(4-O-methyl-α-D-glucopyranosyl uronic acid)-D-xylopyranose. Methanolysis and hydrolysis of the fully methylated hemicellulose (fraction II) gave a mixture of 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyl uronic acid)-3-O-methyl-D-xylopyranose in the approximate molar ratio of 1.6:34:1:6.4. The number-average molecular weight of the methylated polysaccharide was 18,400 ± 500 (degree of polymerization, 110 ± 3). The number-average molecular weight of the original hemicellulose (fraction II) was found to be 23,000 ± 500 (degree of polymerization, 164 ± 3). On the basis of this and other evidences it is suggested that the polysaccharide is composed of chains of 144 (1 → 4)-linked β-D-xylopyranose residues having approximately every seventh residue carrying a terminal 4-O-methyl-α-D-glucuronic acid residue linked through position 2. A small degree of branching in the backbone of D-xylose is indicated.

QUANTITATIVE ASSESSMENT OF THE BRANCHING ARCHITECTURE OF EPDM WITH HIGH CONTENT OF 5-VINYL-2-NORBORNENE AS THIRD MONOMER

2013 ◽  
Vol 86 (4) ◽  
pp. 503-520 ◽  
Author(s):  
Konraad Dullaert ◽  
Gerard van Doremaele ◽  
Martin van Duin ◽  
Herman Dikland
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Quantitative Assessment ◽  
Volume Fraction ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Branched Polymer ◽  
Branching Points ◽  
Gel Permeation ◽  
Branching Architecture

ABSTRACT The branching architecture of high-molecular-weight EPDM polymers with high amounts of 5-vinyl-2-norbornene (VNB) as a third monomer, produced using recently developed Keltan ACE™ technology, was assessed by means of the dilution rheology method proposed by Crosby et al.1 and compared with conventional Ziegler–Natta EPDM grades. First, the dilution rheology results were converted into a single convenient parameter, called the dilution slope. Next, by combining the dilution rheology results with gel permeation chromatography data and assuming trifunctional branching points, we calculated the volume fraction of the branched polymer, the average molecular weight between branching points, and the branching density. It is shown that the high-VNB polymers studied contained a significantly higher amount of branch-on-branch structures.

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