Factors influencing timber gluability with one-part polyurethanes – studied with nine Australian timber species

Holzforschung ◽  
2006 ◽  
Vol 60 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Petri Widsten ◽  
Voytek S. Gutowski ◽  
Sheng Li ◽  
Tony Cerra ◽  
Sharon Molenaar ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Lap Joints ◽  
Sessile Drop Method ◽  
Timber Species ◽  
Adhesion Properties ◽  
Factors Affecting ◽  
X Ray ◽  
Polyurethane Adhesives ◽  
Creep Loading

Abstract The bulk and surface properties of blocks of nine Australian wood species of commercial importance were investigated to elucidate the factors affecting timber gluability with structural one-component polyurethane adhesives. Cross-lap joints were prepared from freshly sanded blocks and the joints were subjected to creep loading in a condensing humidity environment. The median tensile strength (MTS) of the joints was found to improve with decreasing phenolic extractives content, lower timber density and decreasing lipophilic surface extractives content. The latter was assessed from O/C atomic ratios of the timber surfaces determined by X-ray photoelectron spectroscopy (XPS). The content of bulk lipophilic extractives and lignins and wettability of the surface as determined by the sessile drop method did not reveal significant correlations with the adhesion properties. The adhesion tests indicated significant gluability differences between the species investigated.

Surface chemical composition and roughness as factors affecting the wettability of thermo-mechanically modified oak (Quercus robur L.)

Holzforschung ◽  
2018 ◽  
Vol 72 (11) ◽  
pp. 993-1000 ◽  
Author(s):  
Agnieszka Laskowska ◽  
Janusz W. Sobczak
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Glassy Polymers ◽  
Work Of Adhesion ◽  
Densified Wood ◽  
Factors Affecting ◽  
X Ray ◽  
Densification Temperature

AbstractEuropean oak wood (W) was thermo-mechanically modified (TM) via densifying at 100 and 150°C and the surface properties of the TMW were investigated. The contact angle (CA) of the wood with the reference liquids water and diiodomethane was determined using the sessile drop method. The surface free energy of the TMW on tangential sections within the first 60 s after applying a drop was analyzed. The roughness parameters Ra and Rz parallel (‖) and perpendicular (⊥) to the grain were investigated. The wettability analysis showed that densified wood had a higher CA and lower work of adhesion and surface free energy than non-densified wood. An X-ray photoelectron spectroscopy [XPS or electron spectroscopy for chemical analysis (ESCA)] analysis showed that the oxygen to carbon atoms ratio (O/C ratio) of densified wood surface was lower than that of non-densified wood. The carbon C1-C2 atoms ratio (C1/C2 ratio) increased with increasing TM temperature. The results were interpreted as being that extractives migrate to the surface and amorphous and glassy polymers, i.e. lignin and hemicelluloses, in wood are rearranged. Increasing densification temperature makes TMW surfaces more hydrophobic.

scholarly journals Surface-Modified Poly(l-lactide-co-glycolide) Scaffolds for the Treatment of Osteochondral Critical Size Defects—In Vivo Studies on Rabbits

2020 ◽  
Vol 21 (20) ◽  
pp. 7541
Author(s):  
Małgorzata Krok-Borkowicz ◽  
Katarzyna Reczyńska ◽  
Łucja Rumian ◽  
Elżbieta Menaszek ◽  
Maciej Orzelski ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Tissue Regeneration ◽  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Bone Tissue Regeneration ◽  
In Vivo Studies ◽  
In Vivo Model ◽  
Type I ◽  
X Ray

Poly(l-lactide-co-glycolide) (PLGA) porous scaffolds were modified with collagen type I (PLGA/coll) or hydroxyapatite (PLGA/HAp) and implanted in rabbits osteochondral defects to check their biocompatibility and bone tissue regeneration potential. The scaffolds were fabricated using solvent casting/particulate leaching method. Their total porosity was 85% and the pore size was in the range of 250–320 µm. The physico-chemical properties of the scaffolds were evaluated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), sessile drop, and compression tests. Three types of the scaffolds (unmodified PLGA, PLGA/coll, and PLGA/HAp) were implanted into the defects created in New Zealand rabbit femoral trochlears; empty defect acted as control. Samples were extracted after 1, 4, 12, and 26 weeks from the implantation, evaluated using micro-computed tomography (µCT), and stained by Masson–Goldner and hematoxylin-eosin. The results showed that the proposed method is suitable for fabrication of highly porous PLGA scaffolds. Effective deposition of both coll and HAp was confirmed on all surfaces of the pores through the entire scaffold volume. In the in vivo model, PLGA and PLGA/HAp scaffolds enhanced tissue ingrowth as shown by histological and morphometric analyses. Bone formation was the highest for PLGA/HAp scaffolds as evidenced by µCT. Neo-tissue formation in the defect site was well correlated with degradation kinetics of the scaffold material. Interestingly, around PLGA/coll extensive inflammation and inhibited tissue healing were detected, presumably due to immunological response of the host towards collagen of bovine origin. To summarize, PLGA scaffolds modified with HAp are the most promising materials for bone tissue regeneration.

scholarly journals Soil Pollution Characteristics and Microbial Responses in a Vertical Profile with Long-Term Tannery Sludge Contamination in Hebei, China

2019 ◽  
Vol 16 (4) ◽  
pp. 563 ◽  
Author(s):  
Xiangke Kong ◽  
Chunhui Li ◽  
Ping Wang ◽  
Guoxin Huang ◽  
Zhitao Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Soil Profile ◽  
Stable State ◽  
Chemical Properties ◽  
Tannery Sludge ◽  
Factors Affecting ◽  
X Ray ◽  
Degrading Bacteria ◽  
Microbial Responses

An investigation was made into the effects of tannery sludge on soil chemical properties and microbial communities in a typical soil profile with long-term tannery sludge contamination, North China. The results showed that trivalent chromium (Cr(III)), ammonium, organic nitrogen, salinity and sulfide were the predominant contaminants in tannery sludge. Although the tannery sludge contained high chromium (Cr, 3,0970 mg/kg), the proportion of mobile Cr forms (exchangeable plus carbonate-bound fraction) only accounted for 1.32%. The X-ray diffraction and X-ray photoelectron spectroscopy results further demonstrated that the Cr existed in a stable state of oxides and iron oxides. The alkaline loam soil had a significant retardation effect on the migration of salinity, ammonium, Cr(III) and sulfide, and the accumulation of these contaminants occurred in soils (0–40 cm). A good correlation (R2 = 0.959) was observed between total organic carbon (TOC) and Cr(III) in the soil profile, indicating that the dissolved organic matter from sludge leachate promoted the vertical mobility of Cr(III) via forming Cr(III)-organic complexes. The halotolerant bacteria (Halomonas and Tepidimicrobium) and organic degrading bacteria (Flavobacteriaceae, Tepidimicrobium and Balneola) became the dominant microflora in the soil profile. High contents of salinity, Cr and nitrogen were the main environmental factors affecting the abundance of indigenous microorganisms in soils.

scholarly journals Wetting Behavior of LBE on Corroded Candidate LFR Structural Materials of 316L, T91 and CLAM

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 102
Author(s):  
Huiping Zhu ◽  
Xiaochao Du ◽  
Xudong Liu ◽  
Tingxu Yan ◽  
Xiaobo Li ◽  
...  
Keyword(s):  
Sessile Drop ◽  
Element Distribution ◽  
Corrosion Layer ◽  
Corrosion Products ◽  
Martensitic Steels ◽  
Factors Affecting ◽  
X Ray ◽  
High Roughness ◽  
Wetting Behaviors ◽  
Saturated Oxygen

In this work, the wetting behaviors of lead-bismuth eutectic (LBE) on corroded 316L, T91, and CLAM surfaces were studied. The wettability of LBE on virgin and corroded surfaces were tested at 450 °C by using the sessile-drop (SD) method after immersing the samples in LBE with saturated oxygen concentration for 400, 800, and 1200 h at 450°C. Additionally, the morphology, as well as element distribution of the corrosion structure, were characterized by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the virgin samples of three materials are non-wetting to LBE, and the formation of corrosion structures further reduces the wettability. Besides, the thickness of the corrosion layer formed on the 316L surface grew more slowly than the other two steel, which results in better corrosion resistance of austenitic steel 316L than that of ferritic/martensitic steels T91 and CLAM at 450 °C. Meanwhile, the morphology and distribution of corrosion products are important factors affecting the wettability of the steel surface. The formation of corrosion products with high roughness as well as disorder results in a significant reduction in surface wettability.

scholarly journals Adsorption of Pb(II) from Aqueous Solution by Mussel Shell-Based Adsorbent: Preparation, Characterization, and Adsorption Performance

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 741
Author(s):  
Quan Wang ◽  
Fangyuan Jiang ◽  
Xiao-Kun Ouyang ◽  
Li-Ye Yang ◽  
Yangguang Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Raw Material ◽  
Mussel Shell ◽  
Scanning Calorimetry ◽  
Factors Affecting ◽  
X Ray ◽  
Before And After ◽  
Freundlich Adsorption Isotherm ◽  
Mussel Shells ◽  
Shell Powder

As a natural biological adsorbent, shell powder is inexpensive, highly efficient, and does not leave any chemical residue; thus, it can be used to remove contaminants from water. In this study, we used mussel shells as a raw material to prepare an adsorbent. Scanning electron microscopy was used to observe the surface morphology of the mussel shell powder before and after calcination, and X-ray diffraction measurements, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurements were performed to analyze the structure and composition of calcined mussel shell powder. Characterization of the shell powder before and after calcination revealed a change from calcium carbonate to calcium oxide, as well as the formation of a surface porous structure. Using Pb(II) as a representative contaminant, various factors affecting the adsorption were explored, and the adsorption mechanism was analyzed. It was found that the adsorption is consistent with the Freundlich adsorption isotherm and the pseudo second-order model. The calcined mussel shell powder exhibits excellent adsorption for Pb(II), with an adsorption capacity reaching 102.04 mg/g.

scholarly journals Impact of Crystal Habit on the Dissolution Rate and In Vivo Pharmacokinetics of Sorafenib Tosylate

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3469
Author(s):  
Chi Uyen Phan ◽  
Jie Shen ◽  
Kaxi Yu ◽  
Jianming Mao ◽  
Guping Tang
Keyword(s):  
Dissolution Rate ◽  
Photoelectron Spectroscopy ◽  
Class Ii ◽  
Crystal Habit ◽  
Factors Affecting ◽  
X Ray ◽  
Bcs Class Ii ◽  
Rate Limiting Step ◽  
In Vivo Pharmacokinetics

The dissolution rate is the rate-limiting step for Biopharmaceutics Classification System (BCS) class II drugs to enhance their in vivo pharmacokinetic behaviors. There are some factors affecting the dissolution rate, such as polymorphism, particle size, and crystal habit. In this study, to improve the dissolution rate and enhance the in vivo pharmacokinetics of sorafenib tosylate (Sor-Tos), a BCS class II drug, two crystal habits of Sor-Tos were prepared. A plate-shaped crystal habit (ST-A) and a needle-shaped crystal habit (ST-B) were harvested by recrystallization from acetone (ACN) and n-butanol (BuOH), respectively. The surface chemistry of the two crystal habits was determined by powder X-ray diffraction (PXRD) data, molecular modeling, and face indexation analysis, and confirmed by X-ray photoelectron spectroscopy (XPS) data. The results showed that ST-B had a larger hydrophilic surface than ST-A, and subsequently a higher dissolution rate and a substantial enhancement of the in vivo pharmacokinetic performance of ST-B.

scholarly journals Investigation of corrosion and thermal behavior of PU–PDMS-coated AISI 316L

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 355-365
Author(s):  
Muharrem Taşdemir ◽  
Fatih Şenaslan ◽  
Ayhan Çelik
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Polymer Coatings ◽  
Industrial Applications ◽  
Open Circuit ◽  
Stainless Steel Surface ◽  
Aisi 316L ◽  
Cross Sectional ◽  
Adhesion Properties ◽  
X Ray

Abstract Polydimethylsiloxane (PDMS) is widely used from biomedical to industrial applications due to its nontoxic, hydrophobic, and transparent characteristics. PDMS has good thermal and adhesion properties; however, its mechanical properties are comparatively weak. Therefore, PDMS is blended with various polymers to effectively improve its mechanical properties. In this study, polyurethane (PU)–polydimethylsiloxane (PDMS) blended coatings of different concentrations were applied on the AISI 316L stainless steel surface. Their effects on corrosion and tribocorrosion properties were investigated in Ringer’s solutions. The blended polymer coatings were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The thermal properties of samples were examined by TGA and DSC. The surface images and cross-sectional were investigated using scanning electron microscopy (SEM). Tribocorrosion tests were carried out at open circuit potential (OCP). It was determined that hydrophobicity and thermal stability of polymer coating increased, while corrosion resistance slightly decreased with the increasing PDMS concentration in the polymer blended. The friction coefficient of blends decreased as the PU concentration increased. As a result, it was determined that the polymer-coated samples containing up to 50% PDMS prevented corrosive wear under the OCP wear test in Ringer’s solutions.

Study on the Adhesion Properties of Protective Films to the Magnetic Refrigerant Material

2011 ◽  
Vol 239-242 ◽  
pp. 364-367
Author(s):  
Xiao Qiu Zheng ◽  
Yong Ping Ai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Tension Test ◽  
Dc Magnetron Sputtering ◽  
Adhesion Properties ◽  
X Ray ◽  
Magnetic Refrigerant ◽  
Protective Films ◽  
Scanning Electron

Gd substrates were differently coated with Ti and 1Cr18Ni9Ti by means of DC magnetron sputtering technology. The characteristics of the films have been investigated by scanning electron microscopy(SEM), EDS,X-ray photoelectron spectroscopy(XPS),and the adhesion of films were tested by tension test. The results show that the surfaces of films are smooth and perfect, the interferences between Gd and films join together strongly, and the adhesion strengths are larger than 15MPa in these tests.

scholarly journals Structure-Property Relationships of BaCeO Perovskites for the Oxidative Dehydrogenation of Alkanes

1997 ◽  
Vol 497 ◽  
Author(s):  
T. M. Nenoff ◽  
N. B. Jackson ◽  
J. E. Miller ◽  
A. G. Sault ◽  
D. Trudeil
Keyword(s):  
Oxidative Dehydrogenation ◽  
Photoelectron Spectroscopy ◽  
Energy Savings ◽  
Surface Oxygen ◽  
Structure Property ◽  
Weakly Bound ◽  
Complete Combustion ◽  
Factors Affecting ◽  
X Ray ◽  
Dehydrogenation Reactions

ABSTRACTThe oxidative dehydrogenation (ODH) reactions for the formation of two important organic feedstocks ethylene and propylene are of great interest because of the potential in capital and energy savings associated with these reactions. Theoretically, ODH can achieve high conversions of the starting materials (ethane and propane) at lower temperatures than conventional dehydrogenation reactions. The important focus in our study of ODH catalysts is the development of a structure-property relationship for catalyst with respect to selectivity, so as to avoid the more thermodynamically favorable combustion reaction. Catalysts for the ODH reaction generally consist of mixed metal oxides. Since for the most selective catalyst lattice oxygen is known to participate in the reaction, catalysts are sought with surface oxygen atoms that are labile enough to perform dehydrogenation, but not so plentiful or weakly bound as to promote complete combustion. Also, catalysts must be able to replenish surface oxygen by transport from the bulk.Perovskite materials are candidates to fulfill these requirements. We are studying BaCeO3 perovskites doped with elements such as Ca, Mg, and Sr. During the ODH of the alkanes at high temperatures, the perovskite structure is not retained and a mixture of carbonates and oxides is formed, as revealed by XRD. While the Ca doped materials showed enhanced total combustion activity below 600°C, they only showed enhanced alkene production at 700°C. Bulk structural and surface changes, as monitored by powder X-ray diffraction, and X-ray photoelectron spectroscopy are being correlated with activity in order to understand the factors affecting catalyst performance, and to modify catalyst formulations to improve conversion and selectivity.

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