scholarly journals Surface Protection of Wood with Metal Acetylacetonates

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 916
Author(s):  
Yuner Zhu ◽  
Philip D. Evans
Keyword(s):  
Tensile Strength ◽  
Coordination Complexes ◽  
Natural Weathering ◽  
Coordination Complex ◽  
Cross Linking ◽  
Polyurethane Coating ◽  
Metal Acetylacetonates ◽  
Surface Protection ◽  
Uv Absorber ◽  
Nickel Manganese

Metal acetylacetonates are coordination complexes of metal ions and the acetylacetonate anion with diverse uses including catalysts, cross-linking agents and adhesion promotors. Some metal acetylacetonates can photostabilize polymers whereas others are photocatalysts. We hypothesize that the ability of metal acetylacetonates to photostabilize wood will vary depending on the metal in the coordination complex. We test this hypothesis by treating yellow cedar veneers with different acetylacetonates (Co, Cr, Fe, Mn, Ni, and Ti), exposing veneers to natural weathering in Australia, and measuring changes in properties of treated veneers. The most effective treatments were also tested on yellow cedar panels exposed to the weather in Vancouver, Canada. Nickel, manganese, and titanium acetylacetonates were able to restrict weight and tensile strength losses and delignification of wood veneers during natural weathering. Titanium acetylacetonate was as effective as a reactive UV absorber at reducing the greying of panels exposed to 6 months of natural weathering, and both titanium and manganese acetylacetonates reduced the photo-discoloration of panels finished with a polyurethane coating. We conclude that the effectiveness of metal acetylacetonates at photostabilizing wood varies depending on the metal in the coordination complex, and titanium and manganese acetylacetonate show promise as photoprotective primers for wood.

scholarly journals Laboratory Study of Deformation Behaviour of Two New Reinforcing Polymeric TSLs and Their Potential Application in Deep Underground Coal Mine

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2205
Author(s):  
Han Liang ◽  
Jun Han ◽  
Chen Cao ◽  
Shuangwen Ma
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Underground Mining ◽  
Deformation Behaviour ◽  
Polymer Materials ◽  
Surface Protection ◽  
Steel Mesh ◽  
Geological Conditions ◽  
Deep Underground ◽  
Roadway Support

Thin spray-on liner (TSL) is a surface protection technology used by spraying a polymer film, which is widely used for mine airtightness and waterproofing. A reinforcing TSL can replace steel mesh, which is a new method for roadway support. This paper reviews the development of a reinforcing TSL. Considering the deterioration of geological conditions in deep underground mining and the demand for reinforcing automation, two kinds of polymeric reinforcing TSL (RPTSL) materials are developed. The mechanical characteristics of the new TSL materials are studied experimentally. Results show that the average compressive strength, tensile strength, cohesion, and internal friction angle of the two TSL materials are 52 and 32 MPa, 12 and 8 MPa, 6.2 and 17.2 MPa, and 33.6° and 25.9°, respectively. The bonding strength between the two materials and coal is greater than the tensile strength of coal itself, and the mechanical properties of the material for comparison are lower than those of both materials. Based on the TSL support mechanism, we examine the application of the two TSL materials to the mining environment and compare the mechanical properties of polymer materials and cement-based materials. The advantages of polymer materials include versatile mechanical properties, good adhesion, and high early strength. This study provides a new support material to replace steel mesh for roadway surface support, which satisfies the needs of different surface support designs under complex geological conditions, and promotes the automation of roadway support.

scholarly journals A bottom up approach towards artificial oxygenases by combining iron coordination complexes and peptides

2017 ◽  
Vol 8 (5) ◽  
pp. 3660-3667 ◽  
Author(s):  
Olaf Cussó ◽  
Michael W. Giuliano ◽  
Xavi Ribas ◽  
Scott J. Miller ◽  
Miquel Costas
Keyword(s):  
Hydrogen Peroxide ◽  
Coordination Complexes ◽  
Asymmetric Epoxidation ◽  
Coordination Complex ◽  
High Yield ◽  
Aqueous Hydrogen Peroxide ◽  
Bottom Up ◽  
Iron Coordination

The combination of peptides and a chiral iron coordination complex catalyzes high yield highly asymmetric epoxidation with aqueous hydrogen peroxide.

scholarly journals Thermal analysis of halogenated rubber cured with a new cross-linking system

2019 ◽  
Vol 138 (6) ◽  
pp. 4395-4405 ◽  
Author(s):  
Anna Dziemidkiewicz ◽  
Magdalena Maciejewska ◽  
Martyna Pingot
Keyword(s):  
Mechanical Properties ◽  
Cross Linking ◽  
Curing Agent ◽  
Metal Acetylacetonates ◽  
Damping Properties ◽  
Rubber Blends ◽  
Rubber Compounds ◽  
Curing Agents ◽  
Brominated Butyl Rubber ◽  
Thermal Stability Of

Abstract The aim of this work was to examine the influence of new curing agents proposed for brominated butyl rubber (BIIR) on the cross-linking process of rubber compounds and the thermal behavior of the vulcanizates. Rubber blends that were filled with carbon black and contained acetylacetonates of different transition metals in the presence of triethanolamine (TEOA) as new cross-linking agents were prepared. The performed studies showed that metal acetylacetonates (Me(acac)) are effective cross-linking agents for BIIR, which was confirmed by high values of the torque increment (∆M) and significant cross-linking degree of the vulcanizates (α(T)). The most active curing agent seems to be iron acetylacetonate (Fe(acac)). Its application results in a shorter optimal vulcanization time, lower onset vulcanization temperature and similar vulcanization enthalpy compared to the BIIR cured with a sulfur curing system. The BIIR vulcanizates cured with Me(acac) reveal good mechanical properties with tensile strengths in the range of 9–14 MPa and better damping properties comparing to the sulfur-cured rubber. The proposed curing agents do not significantly affect the thermal stability of the BIIR vulcanizates.

Preparation and Application of Electrospinning Membranes of Thermoplastic Carboxymethyl Cellulose/PLA for Removal of Cu2+ from Aqueous Solutions

2012 ◽  
Vol 724 ◽  
pp. 61-64
Author(s):  
Ying Li ◽  
Xiao Yan Lin ◽  
Zhe Chen ◽  
Xue Guang Luo ◽  
Wei Li Zuo
Keyword(s):  
Tensile Strength ◽  
Aqueous Solutions ◽  
Removal Efficiency ◽  
Composite Membrane ◽  
Carboxymethyl Cellulose ◽  
Contact Time ◽  
Electrospinning Process ◽  
Cross Linking ◽  
Initial Concentration ◽  
The Cross

A composite membrane of thermoplastic carboxymethyl cellulose (TCMC) /PLA was prepared by electrospinning process, and crossliked by epichlorohydrin solution at different temperature. The cross-linking temperature was optimized by characterizing the morphology and tensile strength of the film. The optimal cross-linking temperature was 50°C. A composite membrane was used to remove Cu2+ from aqueous solutions, and the effects of initial concentration of Cu2+ and contact time on the removal efficiency of Cu2+ were investigated. The removal efficiency of Cu2+ was 13.78%, at the initial concentration of 40 mg·L-1 and contact time of 30s.

scholarly journals Effect of Addition of Soybean Oil and Gamma-Ray Cross-linking on the Nanoporous HDPE Membrane

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Jong-Seok Park ◽  
Jong-Bae Choi ◽  
Hui-Jeong Gwon ◽  
Youn-Mook Lim ◽  
Myung Seob Khil ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Soybean Oil ◽  
Gamma Rays ◽  
High Density Polyethylene ◽  
Dibutyl Phthalate ◽  
Gamma Ray ◽  
Absorbed Dose ◽  
Electrochemical Stability ◽  
Cross Linking ◽  
Wet Process

A nanoporous high-density polyethylene (HDPE) membrane was prepared by a wet process. Soybean oil and dibutyl phthalate (DBP) were premixed as codiluents, and gamma-rays were used for the cross-linking of HDPE. The pore volume of the nanoporous HDPE membranes with soybean oil was affected by the extracted amount of oil. The tensile strength of the membrane improved with an increasing absorbed dose up to 60 kGy, but decreased at 80 kGy due to severe degradation. The ionic conductivity of the nanoporous HDPE membrane did not really change with an increasing absorbed dose because the pores had already been formed before the gamma-ray radiation. Finally, the electrochemical stability of the HDPE membrane increased when the absorbed dose increased up to 60 kGy.

Tensile strength of handsheets prepared with macerated fibres from solid wood modified with cross-linking agents

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 959-966 ◽  
Author(s):  
Stergios Adamopoulos ◽  
Reza Hosseinpourpia ◽  
Carsten Mai
Keyword(s):  
Tensile Strength ◽  
Strength Loss ◽  
Solid Wood ◽  
Cross Linking ◽  
Microscopic Appearance ◽  
Finite Span ◽  
The Stability ◽  
And Control ◽  
Additional Role ◽  
Modified Wood

Abstract This study was conducted to explain the tensile strength loss of wood due to the modification with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA). Modified and control wood blocks were macerated to deliberate fibres, and handsheets were produced thereof. The nitrogen content of the fibres indicated that maceration removed the major proportions of DMDHEU. The stability of GA in wood during maceration was not assessed. Tensile strength determined at zero span (z-strength) and finite span (f-strength) was equal for the handsheets from DMDHEU-modified fibres and the control handsheets. The microscopic appearance of the tested finite-span paper strips from DMDHEU-modified fibres mainly indicated interfibre failure and did not differ from the fibre fracture mode of the control handsheets. In contrast, the z-strength of the handsheets from GA-modified fibres was lower than that of controls and decreased with increasing content of GA in the initial modified wood. The f-strength behaviour of the handsheets from GA-modified fibres was the opposite: it was higher than that of controls and increased with increasing GA content. The microscopic appearance of the rapture zones of the finite-span testing mainly indicated intrafibre failure for the GA-modified fibres. It was concluded that cross-linking is likely to be the major reason for tensile strength loss of GA- and DMDHEU-modified wood. In terms of DMDHEU-modified wood, the incrustation of the cell wall by the resin and the reduction in pliability could play an additional role.

Influences of Particle Sizes on Properties of Natural Rubber/Waste Ground Rubber Powders Blends

2013 ◽  
Vol 773 ◽  
pp. 668-672
Author(s):  
Jun Liang Liu ◽  
Ping Liu ◽  
Xiao Qiang Tang ◽  
Dong Zeng ◽  
Xing Kai Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Chemical Activation ◽  
Cross Linking ◽  
Particle Sizes ◽  
Elongation At Break ◽  
Tear Strength ◽  
Rubber Waste ◽  
Ground Rubber

In this paper, the blends of natural rubber with waste ground rubber powders have been prepared by mechano-chemical activation method. The influences of particle sizes on both processing performances and mechanical properties have been investigated. The results indicated that: the blends with waste ground rubber powders of smaller particle sizes approached to higher surface tensile and easily mechano-chemical activation, which led to the formation of complete homogenous re-vulcanization cross-linking structure and resulted in the improvements of the whole performances of the final products. The tensile strength, the elongation at break and tear strength approached to the highest value of 20.7MPa, 530% and 33.0 kN/m as the 100mesh waste ground rubber powders were used as the starting materials.

NBR-PANI.DBSA BLENDS: EFFECT OF ELECTRON BEAM IRRADIATION

2013 ◽  
Vol 86 (1) ◽  
pp. 68-85 ◽  
Author(s):  
K. C. Yong
Keyword(s):  
Tensile Strength ◽  
Electron Beam ◽  
Electrical Properties ◽  
Electron Beam Irradiation ◽  
Cross Linking ◽  
Density Level ◽  
Beam Irradiation ◽  
Cross Link ◽  
Electrically Conductive ◽  
Good Potential

ABSTRACT The electron beam irradiation technique was successfully used to cross-link poly(butadiene-co-acrylonitrile)-polyaniline dodecylbenzenesulfonate [NBR-PAni.DBSA] blends. Significant increase in cross-linking densities of all blends with doses of irradiation (up to 200 kGy) was observed, and a reasonably high cross-linking density level (in the order of 1030 m−3) also was achieved. All electron beam–irradiated NBR-PAni.DBSA blends exhibited good tensile properties (with tensile strength up to ∼20 MPa), with values that are comparable to those of similar blends cross-linked with either conventional sulfur or peroxide techniques. This kind of irradiation-induced cross-linking technique (at doses up to 200 kGy) also did not interrupt the blends' electrical properties after the blends were sufficiently stabilized for at least 24 h. The irradiated NBR-PAni.DBSA blends also possessed good electrical properties, that is, a single conductivity percolation threshold and high conductivities up to the order of 10−2 S.cm−1. All of these findings indicate a good potential for using the electron beam irradiation technique to prepare highly cross-linked, electrically conductive NBR-PAni.DBSA blends.

Reduction versus cross-linking: how to improve the tensile strength of graphene oxide/polyvinyl alcohol composite film

2017 ◽  
Vol 4 (8) ◽  
pp. 085601 ◽  
Author(s):  
Cheng-an Tao ◽  
Hao Zhang ◽  
Jian Huang ◽  
Xiaorong Zou ◽  
Hui Zhu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Composite Film ◽  
Cross Linking

A study of roles of different valence of copper oxide interaction with electron beam irradiation in polyethylene composite

2015 ◽  
Vol 30 (7) ◽  
pp. 915-937
Author(s):  
Soo-Tueen Bee ◽  
Lee Tin Sin ◽  
CT Ratnam ◽  
Gin-Khuan Chua ◽  
AR Rahmat
Keyword(s):  
Tensile Strength ◽  
Electron Beam ◽  
Crystallite Size ◽  
Electron Beam Irradiation ◽  
Cross Linking ◽  
Beam Irradiation ◽  
Polyethylene Composite ◽  
Loading Level ◽  
Irradiation Dosage ◽  
Ldpe Composites

The aim of this research was to investigate the interaction of electron beam irradiation on the different valence of copper (I) and copper (II) oxides (Cu2O and CuO) added low-density polyethylene (LDPE) composites. The results showed the increasing of Cu2O loading level in replacing the CuO has significantly reduced the gel content (or degree of cross-linking networks) in LDPE matrix. This is due to the poorer effect of Cu2O in inducing the polymeric free radicals. Meanwhile, the application of low irradiation dosage (≤100 kGy) has significantly increased the crystallite size for crystallite peak (110) of all LDPE composites. However, further increment in irradiation dosages from 100 to 300 kGy has gradually reduced the crystallite size of deflection peak (110). The tensile strength of all LDPE composites was gradually decreased with increasing of Cu2O loading level due to agglomeration of Cu2O and CuO particles in LDPE matrix. In addition, the increasing of irradiation dosages on all Cu2O /CuO added LDPE composites has gradually increased the tensile strength by inducing the formation of the cross-linking networks in LDPE matrix. Nevertheless, the increasing of irradiation dosage has gradually decreased the elongation at break of all Cu2O /CuO added LDPE composites. This is due to the higher degree of cross-linking networks in LDPE matrix could restrict the mobility of LDPE macromolecular chains when subjected to straining stress.

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