Mechanism of calcium phosphate deposition in a hydrothermal coating process

In this study, the influence of employing three different sodium hydroxide (NaOH) pretreatment concentration (1, 3 and 5M) and two cleaning methods (Ultrasonic or Rinse) used in rapid biomimetic coating process on phase composition, function groups, thickness, amount and microstructure of the resulted coating was carried out. Regardless of process parameters, x-ray diffraction and Fourier transform infrared spectroscopy revealed that the all coating mainly comprised octacalcium phosphate and hydroxyapatite as main phases while the microstructure similarly consisted of sharp and interconnected plate-like calcium phosphate (CaP) crystals vertically grown on the surface of titanium. However, the change in sodium hydroxide concentration in pretreatment step and cleaning method influenced the weight change after pretreatment, coating continuity and uniformity, but not the weight change after coating. This could be related to amount of the amorphous alkali gel layer formed during pretreatment step which influenced the rate of coating formation in rapid biomimetic coating process.

Download Full-text

Ultra-Structural Study of the Laminin-Apatite Composite Layer Formed on Ethylene-Vinyl Alcohol Copolymer by a Biomimetic Process

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.284-286.227 ◽

2005 ◽

Vol 284-286 ◽

pp. 227-230 ◽

Cited By ~ 27

Author(s):

Ayako Oyane ◽

Masaki Uchida ◽

Yousuke Ishihara ◽

Atsuo Ito

Keyword(s):

Calcium Phosphate ◽

Amorphous Calcium Phosphate ◽

Vinyl Alcohol ◽

Composite Layer ◽

Apatite Crystal ◽

Coating Process ◽

Ethylene Vinyl Alcohol ◽

Ethylene Vinyl Alcohol Copolymer ◽

Dipping Process ◽

Phase Coating

Mechanism of formation of a laminin-apatite composite layer on the surface of an ethylene-vinyl alcohol copolymer (EVOH) using a liquid phase coating process was investigated by transmission electron microscopy (TEM). In this coating process, an EVOH substrate is alternately dipped in calcium and phosphate solutions, and then immersed in a laminin-containing calcium phosphate (LCP) solution. From the results obtained by the present study, formation of the laminin-apatite composite layer on EVOH is likely to proceed via the following events. By the alternate dipping process, particulate amorphous calcium phosphate, which is a precursor of apatite, was deposited onto the EVOH surface. When the specimen was subsequently immersed in the LCP solution, the amorphous calcium phosphate on the specimen transformed itself into needle-like apatite crystal, and then grew into a layer. During this process, laminin molecules contained in the LCP solution were incorporated into a matrix of the apatite crystals to produce a laminin-apatite composite layer on the EVOH surface.

Download Full-text

Rapid Biomimetic Coating of Calcium Phosphate on Titanium: Effect of Soaking Time, Temperature and Solution Refreshing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.690.81 ◽

2016 ◽

Vol 690 ◽

pp. 81-86 ◽

Cited By ~ 2

Author(s):

Faungchat Thammarakcharoen ◽

Jintamai Suwanprateeb

Keyword(s):

Crystal Structure ◽

Phase Composition ◽

Calcium Phosphate ◽

Octacalcium Phosphate ◽

Solution Temperature ◽

Phosphate Solution ◽

Coating Process ◽

Soaking Time ◽

Biomimetic Coating ◽

The Difference

The influence of employing three different solution temperatures (23, 37 and 50 °C), three soaking times (2, 4 and 6 h) and two solution refreshing methods (Refreshed or Non-refreshed) in rapid biomimetic coating process on phase composition, functional groups, coating content and microstructure of the resulted coating was studied. Increasing soaking times and temperature increased the coating content in all cases regardless of the use of refreshed or non-refreshed accelerated calcium phosphate solution. The use of non-refreshed solution resulted in the lower rate of coating than that of refreshed solution at all coating temperatures. However, all coatings similarly comprised octacalcium phosphate and hydroxyapatite as main phases and the microstructure consisted of sharp and interconnected plate-like crystals vertically grown on the surface of titanium. However, two types of crystal structure were produced. Low solution temperature resulted in isolated spheroids while uniform and distributed crystal structure was produced by using high solution temperature. This could be related to the difference in nucleation and precipitation rate formed in rapid biomimetic coating process as a result of the interplay between temperature and ionic strength of the solutions.

Download Full-text

Economics of coated paper production made from deinked pulp

TAPPI Journal ◽

10.32964/tj12.4.19 ◽

2013 ◽

Vol 12 (4) ◽

pp. 19-27

Author(s):

PATRICK HUBER ◽

LAURENT LYANNAZ ◽

BRUNO CARRÉ

Keyword(s):

Mechanical Properties ◽

Optimization Methods ◽

Coating Process ◽

Coated Paper ◽

Paper Production ◽

Base Paper

The fraction of deinked pulp for coated paper production is continually increasing, with some mills using 100% deinked pulp for the base paper. The brightness of the coated paper made from deinked pulp may be reached through a combination of more or less extensive deinking, compensated by appropriate coating, to optimize costs overall. The authors proposed general optimization methods combined with Kubelka-Munk multilayer calculations to find the most economical combination of deinking and coating process that would produce a coated paper made from DIP, at a given target brightness, while maintaining mechanical properties.

Download Full-text

Depletion of coating color components in the blade coating process circulation

TAPPI Journal ◽

10.32964/tj10.9.17 ◽

2011 ◽

Vol 10 (9) ◽

pp. 17-23 ◽

Cited By ~ 1

Author(s):

ANNE RUTANEN ◽

MARTTI TOIVAKKA

Keyword(s):

Fine Particles ◽

Particle Density ◽

Stable Process ◽

Size Fraction ◽

Color Stability ◽

Strong Interactions ◽

Coating Process ◽

Size Segregation ◽

Coating Color ◽

Average Size

Coating color stability, as defined by changes in its solid particle fraction, is important for runnability, quality, and costs of a paper coating operation. This study sought to determine whether the size or density of particles is important in size segregation in a pigment coating process. We used a laboratory coater to study changes in coating color composition during coating operations. The results suggest that size segregation occurs for high and low density particles. Regardless of the particle density, the fine particle size fraction (<0.2 μm) was the most prone for depletion, causing an increase in the average size of the particles. Strong interactions between the fine particles and other components also were associated with a low depletion tendency of fine particles. A stable process and improved efficiency of fine particles and binders can be achieved by controlling the depletion of fine particles.

Download Full-text