scholarly journals Preparation and Application of Polyurethane Coating Material Based on Epoxycyclohexane-Tetrahydrofuran in Paper Conservation

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1143
Author(s):  
Juan Liu ◽  
Shan-Shan Jin ◽  
Ying-Ping Qi ◽  
Yong-Feng Shen ◽  
Hua Li
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Hexamethylene Diisocyanate ◽  
Proton Nuclear Magnetic Resonance ◽  
Cultural Resources ◽  
Historical Records ◽  
The World ◽  
Folding Endurance ◽  
Paper Conservation ◽  
1Hnmr Spectroscopy

Paper cultural heritages are valuable historical records and also abound in cultural resources. Due to its organic property, paper is susceptible to aging, destruction by environmental pollution and human factors. At present, many countries in the world are facing the problem of paper conservation. Coating reinforcement is one of the methods for paper conservation, in which the choice of reinforcing resin is key. A transparent polyurethane, based on epoxycyclohexane (CHO)-tetrahydrofuran (THF) copolyether, was adopted in this study. The ring-opening polymerization for generating the CHO-THF copolyether took place by the reactants CHO and THF, in the catalysis of boron trifluoride diethyl etherate, initiation of glycerol. Characterizations of the synthetic copolyether were conducted by infrared (IR) spectroscopy and proton nuclear magnetic resonance (1HNMR) spectroscopy. The transparent polyurethane was then produced by the CHO-THF copolyether and hexamethylene diisocyanate (HDI) trimer. The influences of different concentrations of polyurethane solution upon the paper tensile strength, elongation, folding endurance, tearing strength, gloss, and brightness were studied. These findings suggest that 10% polyurethane solution is optimal, not only for greatly improving the paper performance, but also for keeping with the principle of “repair as old”. The applied results demonstrate that the polyurethane based on the CHO-THF copolyether has the characteristics of copolyether along with polyurethane, displaying good mechanical properties in paper reinforcement.

scholarly journals Preparation and Application of Polyurethane Coating Material Based on Epoxycyclohexane-Epoxychloropropane Protective for Paper

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1005 ◽  
Author(s):  
Juan Liu ◽  
Shan-Shan Jin ◽  
Ying-Ping Qi ◽  
Yong-Feng Shen ◽  
Hua Li
Keyword(s):  
High Performance ◽  
Hexamethylene Diisocyanate ◽  
Proton Nuclear Magnetic Resonance ◽  
Paper Strength ◽  
Arduous Task ◽  
Folding Endurance ◽  
Polyether Polyol ◽  
1Hnmr Spectroscopy ◽  
Tearing Strength ◽  
Cultural Relics

Paper historic relics are of great value to research and preserve. However, with the change of environment, paper cultural relics are constantly aging and damaged. Therefore, the reinforcement and conservation of the paper is an important topic in the field of cultural relics protection; thus, it is a crucial and arduous task to discover high-performance protective materials. The coating reinforcement method is a kind of commonsense method to strengthen the paper. Additionally, it is key to select appropriate reinforcing resins. Polyurethane has influence on the improvement of paper strength, stability, and appearance. The epoxycyclohexane-epoxychloropropane polyether polyol was prepared with epoxycyclohexane and epoxychloropropane as materials, glycerol as the initiator, boron trifluoride diethyl etherate as the catalyst, and dichloromethane as the solvent. Infrared (IR) spectroscopy as well as proton nuclear magnetic resonance (1HNMR) spectroscopy were adopted to characterize the structure of the synthetic copolyether. Then, polyurethane based on epoxycyclohexane-epoxychloropropane was prepared by the synthetic copolyether reacting with hexamethylene diisocyanate (HDI) trimer. The effect of the mass concentration of polyurethane on the tensile strength, elongation, folding endurance, and the tearing strength of paper samples were tested. When 10% polyurethane solution was applied to paper, not only were the mechanical properties greatly improved, but the gloss and brightness also changed slightly, which conformed to the principle of “repair as old”. The above results indicate that the synthetic polyurethane combines the advantages of epoxycyclohexane-poxychloropropane polyether polyol along with polyurethane, presenting excellent properties in paper reinforcement or conservation.

scholarly journals Original Macromolecular Architectures Based on poly(ε-caprolactone) and poly(ε-thiocaprolactone) Grafted onto Chitosan Backbone

2018 ◽  
Vol 19 (12) ◽  
pp. 3799 ◽  
Author(s):  
Cüneyt Ünlü ◽  
Eric Pollet ◽  
Luc Avérous
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Hexamethylene Diisocyanate ◽  
Proton Nuclear Magnetic Resonance ◽  
High Yield ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Molar Ratios ◽  
Grafting Onto

Polyester and/or polythioester grafted chitosan copolymers were synthesized. For that, poly(ε-caprolactone) (PCL), poly(ε-thiocaprolactone) (PTCL), and their copolymers were first synthesized by ring opening polymerization. Copolymers with caprolactone:thiocaprolactone (CL:TCL) molar ratios of 2:1, 1:1, 1:2 were synthesized. All of the synthesized macromolecular architectures were characterized using different spectral (Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H-NMR), X-Ray diffraction (XRD)) and thermal (Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA)) methods. Grafting was then performed according two distinct routes: (i) using a blend of both homopolymers (PCL and PTCL) or (ii) using pre-synthesized copolymers with controlled CL:TCL ratios. Hexamethylene diisocyanate was used as a grafting/coupling agent through urethane bonds with high yield. Grafting preferentially occurred at sulfur sites. The results indicated that PTCL is more reactive and favorable than PCL for grafting onto chitosan. With the homopolymers blend grafting route, the corresponding materials mostly had a higher PTCL portion than expected. To obtain polyester grafted chitosan with a determined CL:TCL ratio, the copolymer grafting route would yield better results.

scholarly journals Preparation and Application of Polyurethane Coating Material Based on Epoxy Cyclohexane Protective for Paper

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 431
Author(s):  
Juan Liu ◽  
Shan-Shan Jin ◽  
Ying-Ping Qi ◽  
Yong-Feng Shen ◽  
Hua Li
Keyword(s):  
Chemical Properties ◽  
Hexamethylene Diisocyanate ◽  
Proton Nuclear Magnetic Resonance ◽  
Paper Strength ◽  
Weak Stability ◽  
Excellent Performance ◽  
Folding Endurance ◽  
Physical And Chemical ◽  
1Hnmr Spectroscopy ◽  
And Chemical Properties

Paper is important to most historical and cultural relics, however, these paper heritages are facing a crisis of disappearance, damage and aging. For increasing the paper strength, delaying the paper aging, and improving the weak stability and permeability of former resins used for paper, another material is necessary to be produced on preservation and protection of the paper items. The synthesis of epoxy cyclohexane polyetherpolyol was as follows: Epoxy cyclohexane was as the starting material, ethylene glycol was as the initiator, boron trifluoride ether was as catalyst, and dichloromethane was as the solvent. The synthesized homopolyether was characterized by infrared (IR) spectroscopy and proton nuclear magnetic resonance (1HNMR) spectroscopy to determine the structure. Then the epoxy cyclohexane homopolyether reacted with the hexamethylene diisocyanate (HDI) trimer, and the polyurethane was obtained. With the tests of the physical and chemical properties of paper samples, it showed that the paper processed with 10% polyurethane liquid had excellent performance, the increase in the tensile strength was from 1105 to 2317 N/m, and the increase in the folding endurance was from 20 to 504 times. What’s more, the paper processed with 10% polyurethane liquid had good brightness and gloss. The results of the paper samples for the test have shown that the synthesized material simultaneously has the advantages of epoxy cyclohexane homopolyether and polyurethane, possessing excellent performance in paper reinforcement. Thus, the synthesized polyurethane material has broad application prospect in paper protection field.

scholarly journals Development of Inherently Flame—Retardant Phosphorylated PLA by Combination of Ring-Opening Polymerization and Reactive Extrusion

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 13 ◽  
Author(s):  
Rosica Mincheva ◽  
Hazar Guemiza ◽  
Chaimaa Hidan ◽  
Sébastien Moins ◽  
Olivier Coulembier ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Ring Opening ◽  
Coupling Reaction ◽  
Reactive Extrusion ◽  
Ring Opening Polymerization ◽  
Hexamethylene Diisocyanate ◽  
Cone Calorimetry ◽  
Loss Cone ◽  
Ul 94

In this study, a highly efficient flame-retardant bioplastic poly(lactide) was developed by covalently incorporating flame-retardant DOPO, that is, 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide. To that end, a three-step strategy that combines the catalyzed ring-opening polymerization (ROP) of L,L-lactide (L,L-LA) in bulk from a pre-synthesized DOPO-diamine initiator, followed by bulk chain-coupling reaction by reactive extrusion of the so-obtained phosphorylated polylactide (PLA) oligomers (DOPO-PLA) with hexamethylene diisocyanate (HDI), is described. The flame retardancy of the phosphorylated PLA (DOPO-PLA-PU) was investigated by mass loss cone calorimetry and UL-94 tests. As compared with a commercially available PLA matrix, phosphorylated PLA shows superior flame-retardant properties, that is, (i) significant reduction of both the peak of heat release rate (pHRR) and total heat release (THR) by 35% and 36%, respectively, and (ii) V0 classification at UL-94 test. Comparisons between simple physical DOPO-diamine/PLA blends and a DOPO-PLA-PU material were also performed. The results evidenced the superior flame-retardant behavior of phosphorylated PLA obtained by a reactive pathway.

Synthesis of ABC Star-Shaped Copolymers via a Combination of Controlled Polymerization Techniques

2011 ◽  
Vol 311-313 ◽  
pp. 1161-1167
Author(s):  
Xiao Bing Wang ◽  
Peng Fu ◽  
Min Ying Liu ◽  
Jian Wei Zhang ◽  
Qing Xiang Zhao
Keyword(s):  
Ethylene Oxide ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Proton Nuclear Magnetic Resonance ◽  
Hydroxyl Group ◽  
Controlled Polymerization ◽  
Star Copolymers ◽  
Poly Ethylene Oxide ◽  
Miktoarm Star ◽  
Poly Ethylene

Two kinds of ABC-type miktoarm star copolymers, poly(α-methylstyrene)-poly(ethylene oxide)-poly(ethoxyethyl glycidylether) (PMS-PEO-PEEGE) and poly(α-methylstyrene)-poly(ethylene oxide)-polyglycidol (PMS-PEO-PG), were synthesized via a combination of anionic polymerization with ring-opening polymerization. Firstly, The poly(α-methyl styryl lithium) (PMS－Li+) was capped by EEGE to form the functionalized poly(α-methylstyrene) with both an active ω-hydroxyl group and an ω’-ethoxyethyl-protected hydroxyl group. Secondly, the PMS-b-PEO block copolymers, star(PMS-PEO-PEEGE) and star(PMS-PEO-PG) copolymers were obtained by the ring-opening polymerization of EO and EEGE via the variation of the functional end group, respectively. Finally, the ethoxyethyl group on the PEEGE arm was hydrolyzed. The obtained miktoarm star copolymers and intermediates were characterized by proton nuclear magnetic resonance (1H-NMR) and size exclusion chromatography (SEC).

A Recommender System for Inverse Design of Polycarbonates and Polyesters

2020 ◽  
Author(s):  
Nathaniel Park ◽  
Dmitry Yu. Zubarev ◽  
James L. Hedrick ◽  
Vivien Kiyek ◽  
Christiaan Corbet ◽  
...  
Keyword(s):  
Ring Opening ◽  
High Performance ◽  
Recommendation System ◽  
Polymeric Materials ◽  
Monomer Conversion ◽  
Design Strategy ◽  
Ring Opening Polymerization ◽  
Inverse Design ◽  
False Negatives ◽  
Accelerate Development

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br>

Archiving the British Raj

2018 ◽  
Author(s):  
Sabyasachi Bhattacharya
Keyword(s):  
Public Sphere ◽  
Colonial Rule ◽  
Historical Records ◽  
The Public ◽  
British Raj ◽  
National Archives ◽  
The World ◽  
The Creation ◽  
The Public Sphere ◽  
Central Archive

The archives are generally sites where historians conduct research into our past. Seldom are they objects of research. Sabyasachi Bhattacharya traces the path that led to the creation of a central archive in India, from the setting up of the Imperial Record Department, the precursor of the National Archives of India, and the Indian Historical Records Commission, to the framing of archival policies and the change in those policies over the years. In the last two decades of colonial rule in India, there were anticipations of freedom in many areas of the public sphere. These were felt in the domain of archiving as well, chiefly in the form of reversal of earlier policies. From this perspective, Bhattacharya explores the relation between knowledge and power and discusses how the World Wars and the decline of Britain, among other factors, effected a transition from a Eurocentric and disparaging approach to India towards a more liberal and less ethnocentric one.

Bisurea and Bisthiourea H-Bonding Organocatalysts for Ring-Opening Polymerization: Cues for the Catalyst Design

2019 ◽  
Vol 52 (23) ◽  
pp. 9232-9237 ◽  
Author(s):  
Rukshika S. Hewawasam ◽  
U. L. D. Inush Kalana ◽  
Nayanthara U. Dharmaratne ◽  
Thomas J. Wright ◽  
Timothy J. Bannin ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Catalyst Design
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