Recovery Angle Research Articles

Structure, mechanical properties and grindability of dental Ti–10Zr–X alloys

This study aimed to investigate the structure, mechanical properties and grindability of a binary Ti–Zr alloy added to a series of alloying elements (Nb, Mo, Cr and Fe). The phase and structure of Ti–10Zr–X alloys were evaluated using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. Three-point bending tests were performed using a desk-top mechanical tester. Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min at each of the four rotational speeds of the wheel (500, 750, 1000 or 1200 m/min). Results were compared with c.p. Ti, which was chosen as a control. Results indicated that the phase/crystal structure, microstructure, mechanical properties and grindability of the Ti–10Zr alloy can be significantly changed by adding small amounts of alloying elements. The alloying elements Nb, Mo, Cr and Fe contributed significantly to increasing the grinding ratio under all grinding conditions, although the grinding rate of all the metals was found to be largely dependent on grinding speed. The Ti–10Zr–1Mo alloy showed increases in microhardness (63%), bending strength (40%), bending modulus (30%) and elastic recovery angle (180%) over those of c.p. Ti, and was also found to have better grindability. The Ti–10Zr–1Mo alloy could therefore be used for prosthetic dental applications if other conditions necessary for dental casting are met.

Structure, mechanical properties, and grindability of dental Ti–Zr alloys

Structure, mechanical properties and grindability of a series of binary Ti-Zr alloys with zirconium contents ranging from 10 to 40 wt% have been investigated. Commercially pure titanium (c.p. Ti) was used as a control. Experimental results indicated that the diffraction peaks of all the Ti-Zr alloys matched those for alpha Ti. No beta-phase peaks were found. The hardness of the Ti-Zr alloys increased as the Zr contents increased, and ranged from 266 HV (Ti-10Zr) to 350 HV (Ti-40Zr). As the concentration of zirconium in the alloys increased, the strength, elastic recovery angles and hardness increased. Moreover, the elastically recoverable angle of Ti-40Zr was higher than of c.p. Ti by as much as 550%. The grindability of each metal was found to be largely dependent on the grinding conditions. The Ti-40Zr alloy had a higher grinding rate and grinding ratio than c.p. Ti at low speed. The grinding rate of the Ti-40Zr alloy at 500 m/min was about 1.8 times larger than that of c.p. Ti, and the grinding ratio was about 1.6 times larger than that of c.p. Ti. Our research suggested that the Ti-40Zr alloy has better mechanical properties, excellent elastic recovery capability and improved grindability at low grinding speed. The Ti-40Zr alloy has a great potential for use as a dental machining alloy.

Structure and properties of silk fibroin modified cotton

In this research, a novel cotton fiber with a silk fibroin (SF) coating was prepared by the oxidation of a cotton thread with sodium periodate and subsequent treatment in a solution of silk fibroin. The structures of both the oxidized cotton samples and the SF modified cotton samples were investigated by Fourier transform infrared (FT-IR) in combination with X-ray photoelectron spectroscopy (XPS) analysis. Other performances such as surface morphology and breaking strength were also studied. The results indicated that the weight of the oxidized cotton samples increased during SF treatment, while that of the un-oxidized cotton (pure cotton) samples reduced after SF treatment. Compared with the pure cotton samples, the oxidized cotton clearly showed a characteristic absorption band at 1730 cm−1 due to the stretching vibration of the C=O double bond of the aldehyde group. After being treated with the SF solution, the oxidized cotton fiber showed a weakened characteristic absorption band at 1730 cm−1 and a new absorption band at round 1540 cm−1, suggesting the formation of C-N bond between aldehyde groups in the oxidized cotton and primary amines in the silk fibroin. The results were also confirmed by XPS analysis. Compared with the oxidized cotton samples, the SF treated cottons had relatively smooth surfaces, similar breaking strength, and the improved wrinkle recovery angles. The results in this research suggest that cotton based materials with protein coating can be achieved without using any other crosslinking agents by the method introduced.

Application of Microbial Transglutaminases in Anti-Crease Finish of Silk Fabric

In this paper, microbial transglutaminase (MTG) was applied to process silk fabric for improving its crease resistance under the prerequisite of maintaining other performances. Not only was the effect of MTG on silk fabric investigated through the Fourier transform infrared spectroscopy (FR), but analysis was also undertaken in the microcosmic structure of fibroin through the scanning electron microscope (SEM). Solo MTG treatment as well as compound treatments of MTG followed by hydrogen peroxide, protease and ultrasonic, all showed that MTG can improve the crease resistance of silk fabric. It also enhanced its tensile breaking strength or amended damage in the tensile breaking strength caused by pretreatments.Simultaneously, comparison with other treatments showed that compound treatment of MTG followed by ultrasonic exerted a better coordinated effect and conferred better performances, which made the wrinkle recovery angle (WRA) increase by 17.4% and tensile breaking strength improve by 11.2% respectively. At the same time, other performances were still maintained well.

Citric Acid Crosslinking of Cellulose Using TiO2 Catalyst by Pad-Dry-Cure Method

TiO2 was used as a catalyst for crosslinking of cellulose using citric acid by pad-dry-cure method. Different factors affecting crosslinking were studied, including TiO2 concentration, curing temperature, curing time, and citric acid concentration. The results obtained indicate that TiO2 has the ability to catalyze crosslinking of cellulose with citric acid. Crease recovery angle increases with increasing TiO2 concentration; the optimum concentration was 0.6% TiO2. Also, crease recovery angle increases with increased curing time, curing temperature, and citric acid concentration. The results of whiteness index and roughness were found to be better than those obtained when using a sodium hypophosphite catalyst. The crosslinking was confirmed by FT-IR spectroscopy. It was also found that crosslinking in the presence of TiO2 has an adverse effect on the samples dyed with reactive and direct dyes.

High-resolution and functional magnetic resonance imaging of the brachial plexus using an isotropic 3D T2 STIR (Short Term Inversion Recovery) SPACE sequence and diffusion tensor imaging

This technical note demonstrates the relevance of the isotropic 3D T2 turbo-spin-echo (TSE) sequence with short-term inversion recovery (STIR) and variable flip angle RF excitations (SPACE: Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions) for high-resolution brachial plexus imaging. The sequence was used in 11 patients in the diagnosis of brachial plexus pathologies involving primary and secondary tumors, and in six volunteers. We show that 3D STIR imaging is not only a reliable alternative to 2D STIR imaging, but it also better evaluates the anatomy, nerve site compression and pathology of the plexus, especially to depict space-occupying tumors along its course. Finally, due to its appropriate contrast we describe how 3D-STIR can be used as a high-resolution mask to be fused with fraction of anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) data of the plexus.

Synthesis of a novel perfluorinated acrylate copolymer containing hydroxyethyl sulfone as crosslinking group and its application on cotton fabrics

An acrylate monomer (2-[(2-hydroxyethyl) sulfonyl] ethyl acrylate) containing hydroxyethyl sulfone as crosslinking group was synthesized and a novel perfluorinated acrylate copolymer (NPAC) was prepared by emulsion polymerization. The average size of the emulsion particles was about 101 nm. NPAC was applied to cotton fabric by a pad–dry–cure process. The finished fabric showed excellent water and oil repellency rating and good washing durability without adding extra crosslinking agent. Some other physical performances of the finished fabrics were examined. The dry wrinkle recovery angle (WRA ( W + F)°) increased to 214°. The tearing and tensile strength retention and whiteness index (WI) of the finished fabric decreased to 70, 63, and 69.7%, respectively, compared with the untreated fabric.

N-METHYLOL POLYACRYLAMIDE CYCLODEXTRIN COMPOSITE AS A STIFFENING AGENT FOR COTTON FABRICS

To chemically attach β- Cyclodextrin molecules to cotton cellulose, N-methylol-acrylamide was used to synthesize a cyclodextrin containing monomer ,which was then grafted onto cellulose fibers .Cyclodextrin are cyclic oligosaccharides cable of forming inclusion complex with large number of organic molecules .The aim of this work is the preparation of activated Cyclodextrin and applied it as finishing agent on cotton fabrics to improve stiffness properties, tensile strength and Crease Recovery Angle .

Reaction Mechanism of Dimethyloldihydroxyethyleneurea/ Alpha-amino Acids Co-reactants on the Crosslinking of Cotton Cellulose in the Presence of Aluminum Sulfate Catalyst

Cotton fabrics were crosslinked with dimethyloldihydroxyethyleneurea (DMDHEU) alone and DMDHEU/alpha-amino acids. The results showed that the values of nitrogen content, dry crease recovery angle and wet crease recovery angle of the crosslinked fabrics were ranked as DMDHEU > DMDHEU/aspartic acid > DMDHEU/glycine > DMDHEU/arginine under the same concentration of crosslinking agent. The reaction rate constant was also in the rank of DMDHEU > DMDHEU/aspartic acid > DMDHEU/glycine > DMDHEU/arginine. This rank agreed with the number of amine groups on the alpha-amino acids. From the data of free energies of activation, we found that the alpha-amino acids could affect the crosslinking reaction. The transition state complex for DMDHEU alone was significantly different from those for DMDHEU/ alpha-amino acids. From infrared spectra, the interaction between alpha-amino acids and aluminum ion was confirmed. The mechanisms of the interaction between alpha-amino acids and aluminum ion and the condensation reaction mechanisms between DMDHEU and alpha-amino acids are suggested in this study. The higher the number of carboxylic acid groups contained in the alpha-amino acids, the higher the crease recovery angle and reaction rate constant.

Hybrids for finishing cotton fabric with durable handle performance

New poly(acrylic acid/epichlorohydrin) hybrids were prepared under different polymerization conditions and the proper hybrid was used as a stiffening agent or what may be called hand builder. The latter was incorporated in dimethyloldihydroxy ethylene urea (DMDHEU) finishing formulation and the onset of this on fabric performance as monitored by nitrogen content, wrinkle recovery angle, tensile strength, stiffness, dyeability, and oily stain release was studied. Durability of the new finish was also examined. Results disclose substantial improvement in fabric performance and imply that the hybrid in question acts as a durable hand builder through fixation via its hydroxyl groups within the DMDHEU finish which, in turn, is chemically bonded to cotton cellulose. Scanning electron microscopy of finished fabric revealed that this chemical bonding resulted in hybrid encapsulation, deposition and/or coating of fabric fibers.

Cyclodextrin-4 Hydroxy benzophenone inclusion complex for UV protective cotton fabric

An inclusion complex was formed by the reaction of β -cyclodextrin (β -CD) with 4-hydroxy benzophenone (4-HBP), since β -CD acts as a hosting molecule for 4-HBP. The inclusion complex was added to a finishing bath containing citric acid (CA) and sodium hypophosphite (SHP) as a catalyst to provide the cotton fabric anti-crease and ultraviolet (UV) protection properties. Ultraviolet protection factor (UPF) is the scientific term used to indicate the amount of UV protection provided to skin by fabric. The factors affecting the performance properties and UPF were studied in detail. It was noted that at 0.25 g β -CD and 4-HBP represent the optimum concentration for both of the UPF and anti-crease properties. Increasing the CA and SHP concentrations lead to an increase in the UPF and the wrinkle recovery angle (WRA), while the tensile strength of the finished fabric decreases. Also increasing the curing temperature and/or prolonging the duration enhanced the UPF and WRA. While the tensile strength decreased significantly, the durability of the UV protective cotton fabric against successive washings was evaluated at different numbers of washing cycles (0, 15, and 30 washing cycle). The finished fabrics show an excellent durability against 30 successive washing cycles.

Functionalization of Cotton Fabric with Vinyltrimethoxysilane

The surface of cotton fabric was successfully functionalized with vinyltrimethoxysilane in order to impart water repellency and wrinkle recovery and to introduce surface vinyl groups (—CH=CH2) to the fabric, which could then be initiated for copolymerization reactions with various monomers. The introduction of active groups onto the fabric surface was evidenced from the universal attenuated total reflectance Fourier transform infrared (UATR-FTIR) spectrum of the treated fabric. The spectrum shows two peaks located at 1410 and 1600 cm—1 (C=C stretch). An additional peak located at 756 cm—1 attributed to Si—O—Si symmetric stretch was also observed. Excellent water contact angle and wrinkle recovery angle values were obtained.

Synthesis and application of reactive stiffening agent based on the methlyolated products of (poly-acrylamide) guar gum polyblends

Polyacrylamid-guar gum polyblends have been prepared via graft copolymerization of acrylamide onto guar gum using KBrO3/thiourea redox system as initiators. In order to obtain polyblends with suitable viscosity and full total conversion the prepared polyblends were subjected to further treatment with K2S2O8. The amide groups in the polyblends are converted to reactive groups through methylolation with formaldehyde, with a view to obtain reactive polyblends. The feasibility of utilization of the obtained reactive polyblends as permanent stiffening agents for cotton fabrics was studied. The reactive polyblends (i.e. methylolated polyblends) was then applied to cotton fabrics using the conventional pad-dry-cure method under various conditions. The influence of curing temperature, duration and type of catalysts (i.e., ammonium sulphate (NH4)2SO4 and ammonium chloride (NH4Cl) on the cross-linking reactions between the reactive polyblends in question and the cotton cellulose was investigated. The efficiency of the cross-linking reaction was monitored via determining nitrogen percentages. Evaluation tests on tensile properties (i.e., tensile strength (TS), and elongation at break (EAB), crease recovery angle (CRA), and stiffness were made. The results obtained indicate that reactive polyblends, the cotton fabrics under the optimum pad-cure conditions arrived at (3%Nmethylol-PAam-GG, 0.5% (NH4)2SO4; curing temperature 140°C, and curing time, 5 min) produces fabric having excellent permanent stiffness, superior tensile strength as compared with that of untreated fabric. Tentative mechanisms, including different chemical events that can occur through the whole course of polymerization, methylolation and cross-linking processes, are reported.

Antimicrobial Fibers Created via Polycarboxylic Acid Durable Press Finishing

An N-halamine precursor, m-aminophenyl hydantoin ( m-APH), which was rendered antimicrobial through exposure to chlorine bleach, was synthesized and was applied on cotton fabric using polycarboxylic acids as crosslinking agents. Particularly, 1,2,3,4-butanetetracarboxylic acid (BTCA) with m-APH treated cotton fabric resulted in the highest increased wrinkle recovery angle and chlorine content simultaneously. Durability and rechargeability were measured through an AATCC test method and antimicrobial efficacy of BTCA/ m-APH treated cotton fabric against Gram-positive and Gram-negative bacteria showed a 6 log reduction within 1 min of contact time.

Characterization about the shape memory behaviour of woven fabrics

In this article, a characterizing method is established for evaluating the shape memory behaviour in fabrics. Shape memory polymers with different recipes are used to finish woven cotton fabrics. In order to evaluate thermo-sensitivity of shape memory fabrics, shape memory angle was measured when the fabrics are immersed in hot water. Difference between wrinkle recovery angle and shape memory angle is distinguished. Moreover, a shape memory coefficient is defined to indicate the shape memory behaviour in fabrics. The efficacy of the evaluation methods is also discussed.

Durable antimicrobial finish of cotton fabrics

AbstractCotton fabrics were treated with Biopag, which does not have any functional groups that are reactive toward cellulose, using crosslinking agents or a binder, for the purpose of imparting a durable antimicrobial finish. In this respect, it was found that the crosslinking agents were more effective than the binder. It was confirmed by FT‐IR that the characteristic split peaks of Biopag were still seen even after repeated launderings. The crosslinking agents deteriorated the whiteness and tensile strength of the Biopag‐treated cotton fabrics, while the wrinkle recovery angles (WRAs) were significantly improved. The one‐step padding of Biopag and the crosslinking agent was found to be superior to the two‐step padding method in which Biopag padding was followed by padding of crosslinking agent in respect of WRA, whereas the whiteness and tensile strength were vice versa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

A Leaching Type Antibacterial Agent in the Easy-care Finishing of Knitted Cotton Fabric

A leaching type antibacterial agent (namely Tinosan® CEL) is incorporated in an easy-care finishing formulation of knitted cotton fabric. Finishing is conducted at different conditions including type of softener (Solusoft® WA 90ET, Leomin® NI-ET, Ultratex® 7723, Sapamin® KLNEW, and Siligen® TX 2490), crosslinker (Arkofix® NG-ET, Fixapret® CPN, and Knittex® FEL), and catalyst (Knittex® Catalyst Mo, NH4Cl, MgCl2 . 6H2O, and ZnSO4) as well as concentrations of `Knittex® FEL/ZnSO4' and Tinosan® CEL besides curing time and temperature. It is found that optimal additives to Tinosan® CEL that afford maximum overall antibacterial activities (against Staphylococcus aureus and Pseudomonas aeruginosa) and hydrophilicity to the fabric finished by the pad-dry-cure method (100% wet pick up; drying at 100°C/5 min; curing at 160°C/5 min) were: Knittex® FEL (50 g/L)/ ZnSO4 (5 g/L) and Siligen® TX2490 (20 g/L) along with a wetting agent (2 g/L) and acetic acid (1 g/L). The impact of Tinosan® CEL alone (bath I), coupled with Siligen® TX2490 (bath II), or both in combination with Knittex® FEL/ZnSO4 (bath III) on whiteness index, surface roughness, drape coefficient, air permeability, bursting strength, abrasion resistance, and crease recovery angle of the fabric is investigated. Analysis of variance (ANOVA) of data obtained is carried out at P-value ≤ 0.05. Moreover, the effect of Tinosan® CEL concentration in bath III on these properties is also studied. Durability of antibacterial activity, expressed as inhibition clear zone, using 10 g/L of Tinosan® CEL in bath I or II continues to 10 washing cycles. However, treatment with bath III attains durability even after 25 washing cycles.

Surface modification of polyester and polyamide fabrics by low frequency plasma polymerization of acrylic acid

AbstractIn this study, the surface characteristics of polyester and polyamide fabrics were changed by plasma polymerization technique utilizing acrylic acid as precursor. This monomer was used to produce hydrophilic materials with extended absorbency. The hydrophilicity, total wrinkle recovery angle (WRA°) and breaking strength of the fabrics were determined prior and after plasma polymerization treatment. The modification of surfaces was carried out at low pressure (<100 Pa) and low temperature (<50°C) plasma conditions. The effects of exposure time and discharge power parameters were optimized by comparing properties of the fabrics before and after plasma polymerization treatments. It was shown that two sides of polyester fabric samples were treated equally and homogeneously in plasma reactor. For polyester fabrics, the minimum wetting time, 0.5 s, was observed at two plasma processing parameters of 10 W–45 min and 10 W–20 min, where untreated fabric has a wetting time of 6 s. For polyester fabrics, the maximum value was obtained at 60 W–5 min with the wrinkle recovery angle of 306° where the untreated fabric has 290°. The optimum plasma conditions for polyamide fabrics were determined as 30 W–45 min where 2 s wetting time was observed. Wrinkle recovery angle of untreated polyamide fabric was 264°. In this study, after plasma polymerization of acrylic acid, wrinkle recovery angle values were increased by 13%. No significant change was observed in breaking strength of both fabrics after plasma treatment. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2318–2322, 2007

Preparation of a multifunctional mulberry silk fabric having hydrophobic and hydrophilic surfaces using VUV excimer lamp

A multifunctional silk fabric has been prepared with one face having hydrophobic and another having hydrophilic properties. Fluorocarbon based finish was used to impart hydrophobicity, followed by irradiation on one side of the fabric with 172 nm UV excimer lamp for imparting hydrophilicity. Treated samples were characterised by contact angle measurements, horizontal wicking, air permeability, bending length, and crease recovery angle. Qualitative and quantitative analysis of the treated surface was carried out by atomic force microscope (AFM). The contact angle decreased with irradiation time on the irradiated surface, without affecting the hydrophobic effect on the other side of the fabric. The wickability of the samples was improved significantly at higher irradiation time of 5 min and 10 min. Upon hydrophobic finish application, the fabric properties such as air permeability, bending length were least affected while the crease recovery was improved noticeably.

A comparison of changes over time in cervical foraminal height after tricortical iliac graft or polyetheretherketone cage placement following anterior discectomy

The authors prospectively evaluated cervical foraminal height changes after anterior cervical discectomy and fusion. To their knowledge, this prospective study is the first in which foraminal height changes over time are compared following the placement of a tricortical graft or a polyetheretherketone (PEEK) cage. The patients were randomly divided in two groups. In one group, 30 patients underwent anterior cervical microdiscectomy and free bone graft (FBG) insertion at 46 levels via the Smith-Robinson technique. The FBG was harvested from the right iliac crest. Another 35 patients underwent the same operation, but fusion was provided by the insertion of PEEK intervertebral cages at 41 levels. Fusion status and the C2-7 Cobb angle, interspace height, and foraminal height changes were observed on anterior, lateral, and oblique radiographs obtained at the 18-month follow-up examination. There were no differences between the groups with regard to clinical recovery, fusion status, and Cobb angle. A significant interspace height reduction was observed in the FBG group during the 1st postoperative month. In the FBG group, the mean heights (+/- standard deviation) of the foramina were 8.2 +/- 2.7 mm preoperatively, 10.8 +/- 2.6 mm on postoperative Day 2, and 8.1 +/- 1.5 mm after 18 months of follow up. In the PEEK cage group, the mean heights were 8.4 +/- 2.8 mm preoperatively, 10.3 +/- 1.1 mm on postoperative Day 2, and 9.6 +/- 1.2 mm after 18 months of follow up. The increase in foraminal height was significantly preserved at the 6th, 12th, and 18th months in the cage group. In both groups the foraminal height increased sufficiently and the nerve root was decompressed postoperatively. The PEEK cages may provide sufficient preservation of foraminal height even 1.5 years after the operation.