scholarly journals Synthesis and Application of a Thermoplastic Plate of Poly(lactide-ε-caprolactone) for Radiation Therapy

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Hongli Li ◽  
Wenzhi Li ◽  
Hongtao Wu ◽  
Dengbang Jiang ◽  
Mingwei Yuan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Shape Memory ◽  
Gel Permeation Chromatography ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Clinical Effects ◽  
Recovery Rates ◽  
Single Screw Extruder ◽  
Molecular Weight Regulator ◽  
Deformation Recovery

In this study, the poly(lactide-ε-caprolactone) (P(LA-CL)) copolymer is synthesized by ring-opening polymerization with glycol used as a molecular weight regulator to adjust the molecular weight of the polymer. The proton nuclear magnetic resonance spectroscopy and gel permeation chromatography (GPC) results demonstrate that the P(LA-CL) copolymer is successfully synthesized, and that the molecular weight can be controlled by the glycol content. The thermoplastic plate is processed with triallyl isocyanurate as a cross-linking agent by a single-screw extruder followed by γ-ray irradiation. Shape memory test results show that the material had the desired shape memory effect, with deformation recovery rates reaching 100%. After secondary stretching of samples, deformation recovery rates are unchanged. The results of mechanical property measurements indicate that with added lactide, the tensile strength is improved and shore hardness is increased by 20%–30%. Data from clinical trials also reveal that the material has good clinical effects in thermoplastic membrane fixation.

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 Microwave-Assisted Catalytic Synthesis of Bio-Based Copolymers from Waste Cooking Oil

2017 ◽  
Author(s):  
Mahrzadi Noureen Shahi ◽  
Muhammad Arshad ◽  
Aman Ullah
Keyword(s):  
Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Waste Cooking Oil ◽  
Attenuated Total Reflection ◽  
Fatty Acid Esters ◽  
Proton Nuclear Magnetic Resonance ◽  
Co Catalyst ◽  
Cooking Oil ◽  
First Time ◽  
Acid Esters

Solvent free copolymerization of epoxides derived from fatty acid esters of waste cooking oil with phthalic anhydride using (salen)CrIII Cl as catalyst and n-Bu4NCl/DMAP as co-catalyst was carried out for the first time under microwave irradiation, where reaction time was reduced from number of hours to minutes. The polyesters were obtained with molecular weight (Mw = 3084-6740 g/mol) and dispersity values (D = 1.18-1.92), when (salen)CrIII Cl/n-Bu4NCl was used as catalysts. While in case of DMAP as a co-catalyst, polyesters with improved molecular weight (Mw = 5537-6925 g/mol) and narrow dispersity values (D = 1.07-1.28) were obtained even at reduced concentrations of (salen)CrIII Cl and DMAP. The obtained products were characterized and evaluated by attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR), proton nuclear magnetic resonance (1H-NMR) spectroscopy, gel permeation chromatography (GPC) and thermogravimetric analysis (TGA) Techniques.

A novel and highly efficient polymerization of sulfomethylated alkaline lignins via alkyl chain cross-linking method

Holzforschung ◽  
2016 ◽  
Vol 70 (4) ◽  
pp. 297-304 ◽  
Author(s):  
Nanlong Hong ◽  
Wei Yu ◽  
Yuyuan Xue ◽  
Weimei Zeng ◽  
Jinhao Huang ◽  
...  
Keyword(s):  
Group Analysis ◽  
Gel Permeation Chromatography ◽  
Water Soluble ◽  
Raw Material ◽  
Low Rank ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
One Pot ◽  
New Family ◽  
High Degree

Abstract A new family of water-soluble lignosulfonate polymers with ultrahigh molecular weight (Mw) was developed based on alkali lignin (AL) as starting material in a one-pot reaction in two steps: sulfomethylation of AL as raw material led to AL-S and this material was subsequently cross-linked via alkylation with 1,6-dibromohexane (alkAL-S). Gel permeation chromatography showed a significant increase of Mw from 5200 Da of AL-S to 201 000 Da of alkAL-S with high degree of alkylation. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy and functional group analysis confirmed the efficient polymerization by a nucleophilic substitution reaction mechanism. Additionally, alkAL-S with high Mw showed unexpected viscosity-reducing effect, stability and good rheological properties on a low-rank coal-water slurry (CWS), which are even better than those obtained by naphthalene sulfonate formaldehyde (NSF) as additive. The adsorption properties of the new products were also characterized via a quartz crystal microbalance combined with dissipation monitoring (QCM-D method). Cross-linked structure, large steric hindrance from high Mw and suitable amphiphilic properties of alkAL-S polymers contribute together to the highly improved dispersion performances for CWS.

Synthesis and Characterization of Poly (styrene-co-butyl acrylate)/Silica Aerogel Nanocomposites by in situ AGET ATRP: Investigating Thermal Properties

2017 ◽  
Vol 36 (10) ◽  
pp. 955-962 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
Butyl Acrylate ◽  
Silica Aerogel ◽  
Size Exclusion ◽  
Proton Nuclear Magnetic Resonance ◽  
Molar Ratio ◽  
Resonance Spectroscopy ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Exclusion Chromatography

AbstractHydrophilic silica aerogel nanoparticles surface was modified with hexamethyldisilazane. Then, the resultant modified nanoparticles were used in random copolymerization of styrene and butyl acrylate via activators generated by electron transfer for atom transfer radical polymerization. Conversion and molecular weight determinations were performed using gas and size exclusion chromatography respectively. Addition of modified nanoparticles by 3 wt% results in a decrease of conversion from 68 to 46 %. Molecular weight of copolymer chains decreases from 12,500 to 7,500 g.mol–1 by addition of 3 wt% modified nanoparticles; however, PDI values increase from 1.1 to 1.4. Proton nuclear magnetic resonance spectroscopy results indicate that the molar ratio of each monomer in the copolymer chains is approximately similar to the initial selected mole ratio of them. Increasing thermal stability of the nanocomposites is demonstrated by thermal gravimetric analysis. Differential scanning calorimetry also shows a decrease in glass transition temperature by increasing modified silica aerogel nanoparticles.

scholarly journals Physicochemical Characterization of Thermally Treated Chitosans and Chitosans Obtained by Alkaline Deacetylation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ana Maria de Oliveira ◽  
Telma Teixeira Franco ◽  
Enio Nazaré de Oliveira Junior
Keyword(s):  
Thermal Treatment ◽  
Kinematic Viscosity ◽  
Molar Mass ◽  
Physicochemical Characterization ◽  
Gel Permeation Chromatography ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Gel Permeation ◽  
Thermal Depolymerization

The thermal depolymerization of chitosan and alkaline deacetylation of chitin were characterized by measurement of viscosity, gel permeation chromatography (GPC), potentiometric titration (PT), and proton nuclear magnetic resonance spectroscopy (H1NMR). The depolymerization rates (DR) measured by kinematic viscosity (KV), apparent viscosity (AV), and GPC (Mw) until 4 h of treatment wereDRKV=21.9,DRAV=25.5, andDRMw=23.3% h-1and for 5 to 10 h of treatment they decreased slowly to produce ofDRKV=0.545,DRAV=0.248, andDRMw=1.11% h-1. The mole fraction of N-acetylglucosamine residuesFAof chitosans was not modified after 10 h of thermal treatment at 100°C. The initialFAvalues of chitosan without any treatment wereFAPT=0.21andFAHNMR1=0.22and of chitosan treated for 10 h wereFAPT=0.27andFAHNMR1=0.22. The variables used to characterize the depolymerization process showed a good correlation. Six hours of thermal treatment as sufficient to obtain chitosans with a molar mass 90% smaller than that of the control chitosan without treatment.

scholarly journals Synthesis of Thermo-Responsive Block-Graft Copolymer Based on PCL and PEG Analogues, and Preparation of Hydrogel via Click Chemistry

2019 ◽  
Author(s):  
Pei Shang ◽  
Jie Wu ◽  
Xiaoyu Shi ◽  
Zhidan Wang ◽  
Fei Song ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Graft Copolymer ◽  
Water Solubility ◽  
Sol Gel ◽  
Cycloaddition Reaction ◽  
Gel Permeation Chromatography ◽  
Proton Nuclear Magnetic Resonance ◽  
Fluorescence Probes ◽  
Resonance Spectroscopy

The cross-linkable PCL-PEG analogues block-graft copolymer was designed and synthesized, which with the copolymer of the MEO2MA and OEGMA as graft chains to improve the mPEG-b-PCL-b-mPEG copolymer the aqueous solution properties. And successfully prepared two hydrogels via a copper-catalyzed 1, 3-dipolar azide-alkyne cycloaddition reaction of alkyne-terminated poly[glycidyl methacrylate-co-2-(2-methoxyethoxy) ethyl methacrylate-co-oligo (ethylene glycol) methacrylate] [P(GMA-co-MEO2MA-co-OEGMA)] with azide end-functionalized PCL-PEG analogues block-graft copolymer, and tetrakis (2-propynyloxymethyl) -methane (TPOM) and with azide end-functionalized PCL-PEG analogues block-graft copolymer. The copolymer's chemical structure was characterized by proton nuclear magnetic resonance spectroscopy and fourier transform infrared spectroscopy. The molecular weights of the copolymers were decided with gel permeation chromatography. The water solubility and temperature sensitivity of the copolymers were studied by taking digital photos and transmittance change measured by UV spectrophotometer at different temperatures. Fluorescence probes, surface tension, dynamic light scattering and transmission electron microscopy were used to analyze the micelles that copolymers self-assembly in aqueous solution. The sol-gel behavior of copolymer solutions at high concentrations was explored by vial inversion experiments. Finally, the network structure of the gels was observed by scanning electron microscopy. These conclusions indicate that these hydrogels are expected to be used as a new material in the field of biomedicine.

Novel comonomer synthesis from thiophene-2-carbonyl chloride and polydimethylsiloxane modified cyclohexanone formaldehyde resin

2014 ◽  
Vol 43 (5) ◽  
pp. 277-284 ◽  
Author(s):  
Nilgun Kizilcan ◽  
Merve Istif
Keyword(s):  
Molecular Weight ◽  
Chemical Oxidation ◽  
Proton Nuclear Magnetic Resonance ◽  
Esterification Reaction ◽  
Formaldehyde Resin ◽  
Resonance Spectroscopy ◽  
Hydroxyl Groups ◽  
Content Type ◽  
Carbonyl Chloride ◽  
Oxidation System

Purpose – The purpose of this paper is to produce an electroactive monomer containing ketonic resins and then to investigate redox reaction between Fe+3 and bounded thiophene in comonomers. First, thiophene functionalised ketonic resins (Th-CFPDMSR) were synthesised by esterification reaction of thiophene-2-carbonyl chloride (ThCCl) and hydroxyl groups of cyclohexanone formaldehyde resin (CFR). Th-CFPDMSR was then polymerised by ferric salt. Thiophene modified ketonic resins (Th-CFPDMSR) as comonomers were characterised by common techniques such as gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimeter and scanning electron microscope. Design/methodology/approach – Th-CFPDMSR comonomers were synthesised by esterification reaction of ThCCl and hydroxyl groups of ketonic resins. Then, the in-situ chemical oxidation (ISCO) of ThC-CFR in the presence of iron (III) chloride salt (FeCl3) was accomplished in chloroform/acetonitrile mixture solutions at room temperature. Findings – Important structural factor determined quantitatively for Th-CFPDMSR is the CFPDMS/TCCl ratio after reaction. The mole ratio effect of TCCl and ketonic resin on the solubility, molecular weight, melting temperature (Tm) and glass transition temperature (Tg) values of the comonomers (TCCl-CFPDMSR) was investigated. Research limitations/implications – The ferric ion (Fe+3) has a standard oxidation potential. Furthermore, FeCl3 can react with thiophene to produce a cation radical. FeCl3 cannot react with hydroxyl groups of ketonic resins. When ferric is used for ISCO application at relatively low temperatures (e.g. < 20°C), the oxidation reactions are usually less aggressive. Practical implications – This work provides technical information for the synthesis of conducting block copolymer and for the synthesis of chain-extended resins. The modified resins contain thiophene. The chemical oxidation system has been used to polymerise these thiophene groups, and resins with much higher molecular weight might be produced. The resins may also promote the adhesive strength of a coating and corrosion inhibition to metal surfaces of a coating. Originality/value – Novel Th-CFPDMSR comonomers were synthesised. These comonomers have higher Tg and Tm values than CF-PDMSR alone. The chemical oxidation system has been used to polymerise these thiophene functionalised ketonic resins.

Ultra-low-molecular-weight heparins: Precise structural features impacting specific anticoagulant activities

2013 ◽  
Vol 109 (03) ◽  
pp. 471-478 ◽  
Author(s):  
Marcelo Lima ◽  
Christian Viskov ◽  
Frederic Herman ◽  
Angel Gray ◽  
Eduardo de Farias ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Structural Data ◽  
Monosaccharide Composition ◽  
Structural Features ◽  
Therapeutic Agents ◽  
Resonance Spectroscopy ◽  
Low Molecular Weight ◽  
Low Molecular Weight Heparins ◽  
Molecular Weights

SummaryUltra-low-molecular-weight heparins (ULMWHs) with better efficacy and safety ratios are under development; however, there are few structural data available. The main structural features and molecular weight of ULMWHs were studied and compared to enoxaparin. Their monosaccharide composition and average molecular weights were determined and preparations studied by nuclear magnetic resonance spectroscopy, scanning ultraviolet spectroscopy, circular dichroism and gel permeation chromatography. In general, ULMWHs presented higher 3-O-sulphated glucosamine and unsaturated uronic acid residues, the latter being comparable with their higher degree of depolymerisation. The analysis showed that ULMWHs are structurally related to LMWHs; however, their monosaccharide/oligosaccharide compositions and average molecular weights differed considerably explaining their different anticoagulant activities. The results relate structural features to activity, assisting the development of new and improved therapeutic agents, based on depolymerised heparin, for the prophylaxis and treatment of thrombotic disorders.

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