WaxPedia - User contributions [en]

Adhesives

2013-08-28T20:20:50Z

Wikimc:

An adhesive may be defined as material which applied to surfaces of materials can joint and resist separation. Adhesive is the general term and includes cement, glue, paste, etc. The term adhesion is used when referring to the attraction between the substances<ref>Kinloch, A.J. Adhesions and Adhesives, Science and Technology. First edition, p. 1</ref>.

=A Brief History of Adhesives=

We can appreciate the adhesive function on nature, marine organism are attach to hard substrates due to secreted adhesive; this adhesive are able to displace water, spread and form adhesive bonds with the substrate<ref>Dickinson, G.H., Vega, E.I., Wahl, K.J., Orihuela, B., Beyley, V. (2009) Barnacle cement: a polymerization model based on evolutionary concepts. The Journal of Experimental Biology 212, 3499-3510</ref>; many insects secrete a fluid-base adhesive that allows climb and walk upside down on diverse substrates<ref>Drechsler, P., Federle, W. (2006) Biomechanics of smooth adhesive pads in insects: influence of tarsal secretion on attachment performance. Comp Physiol A 192:1213–1222</ref>
<ref>Gorb, S.N., Sinha, M., Peressadko, A. (2007) Insects did it first: a micropatterned adhesive tape for robotic applications. Bioinsp. Biomim. 2 S117–S125</ref> and some birds use their saliva to hold their nests together.
The uses of adhesives by the human being remote to ancient times, when some natural materials were melted on a rock by the action of the sun, and this materials shown sticky properties; some of the other materials used by early human beings as adhesives are now called beeswax, rosin, rubber, shellac, sulfur, tar, and vegetable gums<ref>Pizzi, A., Mittal, K.L. Handbook of adhesive Technology. Second edition</ref>. The mainly use for this materials were: developed tools and as sealants for warrens.

The Egyptians utilized gum Arabic from the acacia tree, egg, glue, semiliquid balsams, and resins from trees. Wooden coffins were decorated with pigments bonded with “gesso”, a mixture of chalk and glue. Glues from fish, stag horns, and cheese (Glutine casei) were known in the days of Theophilus for fixing together wooden objects<ref>Skeist, I. Handbook of adhesives. Third edition, p. 4</ref>.

The first commercial glue plant was founded in Holland in 1690, that casein glues appear to have been manufactured in Germany and Switzerland in the early nineteenth century, and that the first U.S. patent (number 183,024) on a casein glue was issued in 1876<ref>Pizzi, A., Mittal, K.L. Handbook of adhesive Technology. Second edition</ref>.

=Wax in Adhesives=
Adhesives due to its transition from fluid to solid, are involved in many industries: electronic, wood, textiles, rubber and plastics, sealants, etc. There is a growth of adhesives in industry, and so the use of waxes in adhesives. The various functions of wax in the adhesives may be summed as follows<ref>Warth, A.H. The chemical and technology of waxes. Second edition, p. 636</ref>:

a) As a laminating adhesive, with or without the aid of other material, such as rubber, resin, etc.

b) As a protective coating for wrapping which will by the aid of heat act as a “self-sealing” agent.

c) As an ingredient of “hot melt” cement – useful in sticking dissimilar material together.

d) As an ingredient of the sticky surfacing agent for paper material, such as flypaper.

e) As a lubricator in glues; and as flexing agent in adhesives.

f) As a combining agent with rubber-wax adhesive which can be applied by heat to the end of a shot cartridge.

=References=
<references/>

Hot melt

2013-08-28T20:15:56Z

Wikimc:

A hot melt adhesive is a thermoplastic material, solid at room temperature, which is applied in its molten form and will adhere to a surface when cooled.

The wax is used as an additive in hot melt adhesive composition, which is used in bonding articles such as those made from fibrous cellulosic materials, plastic, wood, metal, etc.

=A Brief History of hot melt=

When some natural materials fell on rocks heated by the sun, they softened and became sticky, and later hardened in the cool of the night. Observers made use of these natural phase-change materials as they chanced upon them. When lightning started fires some materials melted and then cooled in interesting shapes. Observers, using the fires to harden their sharpened stick weapons, put out the fires by rubbing their sticks on the ground, and some contacted and melted resins, which when cooled, again hardened. Thus was born the technology we now call hot-melt adhesives.

=Hot melt properties=
All the thermoplastics adhesives require heating in order to melt the polymer, hence the name “hot-melt”. The time a hot melt adhesive takes to solidify to a point where it can no longer bond is called the ‘open time´. The time required for the adhesive to cool to the point where is has enough strength to form a bond is the ‘set speed´. These properties are optimized with the addition of waxes and resins with certain properties.

Hot melt

2013-08-28T17:48:00Z

Wikimc:

A hot melt adhesive is a thermoplastic material, solid at room temperature, which is applied in its molten form and will adhere to a surface when cooled.

The wax is used as an additive in hot melt adhesive composition, which is used in bonding articles such as those made from fibrous cellulosic materials, plastic, wood, metal, etc.

=A Brief History of hot melt=

When some natural materials fell on rocks heated by the sun, they softened and became sticky, and later hardened in the cool of the night. Observers made use of these natural phase-change materials as they chanced upon them. When lightning started fires some materials melted and then cooled in interesting shapes. Observers, using the fires to harden their sharpened stick weapons, put out the fires by rubbing their sticks on the ground, and some contacted and melted resins, which when cooled, again hardened. Thus was born the technology we now call hot-melt adhesives.

=Hot melt properties=
All the thermoplastics adhesives require heating in order to melt the polymer, hence the name “hot-melt”. The time a hot melt adhesives takes to solidify to a point where it can no longer bond is called the ‘open time´. The time required for the adhesive to cool to the point where is has enough strength to form a bond is the ‘set speed´. These properties are optimized with the addition of waxes and resins with certain properties.
The low viscosity of the wax is used to reduce the high viscosity of the polymer and resin to ensure efficient mixing. This reduction in viscosity is particularly important during the application stage. A low viscosity is required to pump the molten adhesive from the storage tank to the application area and to ensure proper surface wetting when applied

2013-08-15T17:13:58Z

Wikimc: /* USP 401 */

The ester value is the number of mg of potassium hydroxide required to saponify the esters in 1.0 g of the substance.<ref name="multiple">Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p.586</ref>

=Wax esters=

Wax esters are oxoesters of long-chain fatty acids esterified with long-chain alcohols. The ester value shows the amount alkali consumed in the saponification of the esters<ref>Pharmacopedia/National Formulary. US., Vol. 1, 2009, p. 150</ref> and is possible identify and differentiate the waxes with this value; for example beeswax ester value is 72 to 79 mg KOH/ g, candelilla wax ester value is 31 to 43 mg KOH/g and carnauba wax ester value is 74 to 78 mg KOH/g.

=Method=
In ester value determination, the sample is hydrolysed to alcohol and using excess of standar potassium hydroxide solution. The excess of alkali is back titrated.
USP-NF monographs presents a general procedure of ester value apply to fats, fixed oils and waxes.

==USP 401==
Place 1.5 g to 2 g of the substance in a tared, 250 mL flasks, add 20 mL to 30 mL of neutralized alcohol and shake. Add 1 mL of phenolphthalein, and titrate with 0.5 N alcoholic potassium hydroxide until the free acid is neutralized. Add 25.0 mL of 0.5N alcoholic potassium hydroxide. Heat the flask on a steam bath, under a suitable condenser to maintain reflux for 30 minutes, frequently rotating the contents titrate the excess potassium hydroxide with 0.5 N hydrochloric acid. Perform a blank determination under the same conditions. Calculate the ester value by the formula:

[[Archivo:Ester value1.jpg|280x280px|centro|]]

BHCl: is the volume in mL, of the hydrochloric acid consumed by the blank

VHCl: is the volume in mL, of the hydrochloric acid consumed by the actual test

W: is the weight, in g, of the sample taken

It is possible to perform this test using the sample at the end of determination of acid value, adding 15 mL of potassium hydroxide 0.5 N and heat the flask under a suitable condenser to maintain reflux for 3-4 h. Titrate the excess potassium hydroxide with 0.5 N hydrochloric acid (until the sample turns white). Perform a blank determination under the same conditions. Register the volume of hydrochloric acid consumed for the sample as the well blank. Calculate ester value by the formula:

[[Archivo:Estervalue.jpg|280x280px|centro|]]

BHCl: is the volume in mL, of the hydrochloric acid consumed by the blank

VHCl: is the volume in mL, of the hydrochloric acid consumed by the actual test

NHCl: is the normality of the hydrochloric acid

56.1: is the molecular weight of potassium hydroxide

W: is the weight, in g, of the sample taken

=Referencia=
<references />

File:Estervalue.jpg

2013-08-15T17:06:53Z

Wikimc:

File:Ester value1.jpg

2013-08-15T17:06:31Z

Wikimc:

Acid Value

2013-08-14T22:32:32Z

Wikimc:

Ester value

2013-08-14T22:19:13Z

Wikimc:

The ester value is the number of mg of potassium hydroxide required to saponify the esters in 1.0 g of the substance.<ref name="multiple">Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p.586</ref>

=Wax esters=

Wax esters are oxoesters of long-chain fatty acids esterified with long-chain alcohols. The ester value shows the amount alkali consumed in the saponification of the esters<ref>Pharmacopedia/National Formulary. US., Vol. 1, 2009, p. 150</ref> and is possible identify and differentiate the waxes with this value; for example beeswax ester value is 72 to 79 mg KOH/ g, candelilla wax ester value is 31 to 43 mg KOH/g and carnauba wax ester value is 74 to 78 mg KOH/g.

=Method=
In ester value determination, the sample is hydrolysed to alcohol and using excess of standar potassium hydroxide solution. The excess of alkali is back titrated.
USP-NF monographs presents a general procedure of ester value apply to fats, fixed oils and waxes.

==USP 401==
Place 1.5 g to 2 g of the substance in a tared, 250 mL flasks, add 20 mL to 30 mL of neutralized alcohol and shake. Add 1 mL of phenolphthalein, and titrate with 0.5 N alcoholic potassium hydroxide until the free acid is neutralized. Add 25.0 mL of 0.5N alcoholic potassium hydroxide. Heat the flask on a steam bath, under a suitable condenser to maintain reflux for 30 minutes, frequently rotating the contents titrate the excess potassium hydroxide with 0.5 N hydrochloric acid. Perform a blank determination under the same conditions. Calculate the ester value by the formula:

It is possible to perform this test using the sample at the end of determination of acid value, adding 15 mL of potassium hydroxide 0.5 N and heat the flask under a suitable condenser to maintain reflux for 3-4 h. Titrate the excess potassium hydroxide with 0.5 N hydrochloric acid (until the sample turns white). Perform a blank determination under the same conditions. Register the volume of hydrochloric acid consumed for the sample as the well blank. Calculate ester value by the formula:

=Referencia=
<references />

Acid Value

2013-08-14T17:54:46Z

Wikimc:

Acidity is frequently expressed as the Acid Value, which is the number of mg of potassium hydroxide required to neutralize the free acids in 1.0 g of the substance<ref>Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 586</ref>.

=Methods=
The acid value of a wax is determined by dissolving a known amount of the wax in alcohol and titrating the solution against standard alkali solution.

[[Archivo:Acid_reaction.jpg|380x380px|centro|]]

==USP 401==
The acidity of fats and fixed oils in USP may be expressed as the number of mL of 0.1 N alkali required to neutralize the free acids in 10.0 g of substance<ref>Pharmacopedia/National Formulary. US., Vol. 1, 2009, p. 150</ref>.

Weigh 3 g of sample and place it in a clean 250 mL Erlenmeyer flask. Place 50 mL of solvent (isopropyl alcohol-toluene 5:4) connect the flask with a suitable condenser and warm slowly, with frequent shaking, until the sample dissolves. Remove the flask from the condenser and add 1 mL of phenolphthalein in isopropyl alcohol.
Shake vigorously while titrating with 0.1 N potassium hydroxide. Register the volume of potassium hydroxide consumed.Calculate Acid value by the formula:

[[Archivo:Diapositiva1.JPG|180x180px|centro|]]

Where:

56.11: is the molecular weight of potassium hydroxide

V: is the volume in mL

N: is the normality of the potassium hydroxide solution

W: is the weight, in g, of the sample taken

==Referencia==

<references />

Acid Value

2013-08-14T17:54:25Z

Wikimc: /* Methods */

Acidity is frequently expressed as the Acid Value, which is the number of mg of potassium hydroxide required to neutralize the free acids in 1.0 g of the substance<ref>Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 586</ref>.

=Methods=
The acid value of a wax is determined by dissolving a known amount of the wax in alcohol and titrating the solution against standard alkali solution.

[[Archivo:Acid_reaction.jpg|380x380px|centro|]]

==USP 401==
The acidity of fats and fixed oils in USP may be expressed as the number of mL of 0.1 N alkali required to neutralize the free acids in 10.0 g of substance<ref>Pharmacopedia/National Formulary. US., Vol. 1, 2009, p. 150</ref>.

Weigh 3 g of sample and place it in a clean 250 mL Erlenmeyer flask. Place 50 mL of solvent (isopropyl alcohol-toluene 5:4) connect the flask with a suitable condenser and warm slowly, with frequent shaking, until the sample dissolves. Remove the flask from the condenser and add 1 mL of phenolphthalein in isopropyl alcohol.
Shake vigorously while titrating with 0.1 N potassium hydroxide. Register the volume of potassium hydroxide consumed.Calculate Acid value by the formula:

[[Archivo:Diapositiva1.JPG|180x180px|centro|]]

Where:

56.11: is the molecular weight of potassium hydroxide

V: is the volume in mL

N: is the normality of the potassium hydroxide solution

W: is the weight, in g, of the sample taken

==Referencia==

<references />

Acid Value

2013-08-14T17:53:48Z

Wikimc:

Acidity is frequently expressed as the Acid Value, which is the number of mg of potassium hydroxide required to neutralize the free acids in 1.0 g of the substance<ref>Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 586</ref>.

=Methods=
The acid value of a wax is determined by dissolving a known amount of the wax in alcohol and titrating the solution against standard alkali solution.

[[Archivo:Acid_reaction.jpg|180x180px|centro|]]

==USP 401==
The acidity of fats and fixed oils in USP may be expressed as the number of mL of 0.1 N alkali required to neutralize the free acids in 10.0 g of substance<ref>Pharmacopedia/National Formulary. US., Vol. 1, 2009, p. 150</ref>.

Weigh 3 g of sample and place it in a clean 250 mL Erlenmeyer flask. Place 50 mL of solvent (isopropyl alcohol-toluene 5:4) connect the flask with a suitable condenser and warm slowly, with frequent shaking, until the sample dissolves. Remove the flask from the condenser and add 1 mL of phenolphthalein in isopropyl alcohol.
Shake vigorously while titrating with 0.1 N potassium hydroxide. Register the volume of potassium hydroxide consumed.Calculate Acid value by the formula:

[[Archivo:Diapositiva1.JPG|180x180px|centro|]]

Where:

56.11: is the molecular weight of potassium hydroxide

V: is the volume in mL

N: is the normality of the potassium hydroxide solution

W: is the weight, in g, of the sample taken

==Referencia==

<references />

2013-08-14T16:34:47Z

Wikimc: /* Methods */

Acidity is frequently expressed as the Acid Value, which is the number of mg of potassium hydroxide required to neutralize the free acids in 1.0 g of the substance<ref>Warth, A. H.; The Chemistry and Technology of Waxes. Reinhold Publishing Corporation. Second Edition, p. 586</ref>

=Methods=
The acid value of a wax is determined by dissolving a known amount of the wax in alcohol and titrating the solution against standard alkali solution.

==USP 401==
The acidity of fats and fixed oils in USP may be expressed as the number of mL of 0.1 N alkali required to neutralize the free acids in 10.0 g of substance.

Weigh 3 g of sample and place it in a clean 250 mL Erlenmeyer flask. Place 50 mL of solvent (isopropyl alcohol-toluene 5:4) connect the flask with a suitable condenser and warm slowly, with frequent shaking, until the sample dissolves. Remove the flask from the condenser and add 1 mL of a 1% solution of phenolphthalein in isopropyl alcohol.
Shake vigorously while titrating with 0.1 N potassium hydroxide. Register the volume of potassium hydroxide consumed.

[[Archivo:Diapositiva1.JPG|180x180px|miniaturadeimagen|centro|]]

==Referencia==

<references />

2013-08-08T21:52:45Z

Wikimc:

==Tests and thecniques==
:1.1 Structure
:1.2 Chemical properties
::1.2.1 [[Acid Value]]
::1.2.2 [[Ester value]]
::1.2.3 [[Saponification value]]
::1.2.4 [[Iodine value]]
::1.2.5 [[Hidroxyl and Acetyl numbers]]
:1.3 Determination of Physical Constants
::1.3.1 [[Melting Point]]
::1.3.2 [[Penetration Test]]
::1.3.3 [[Color]]
::1.3.4 [[Odor]]
::1.3.5 [[Softening Point]]
 

==Industrial Uses of waxes ==
:2.1 Food
:2.2 Adhesives
:2.3 Textile
:2.4 Cosmetics
:2.5 Coatings
:2.6 Explosives
 
==Composition ==
:3.1 Synhetic
:3.2 Natural
:3.3 Mixed
 
==Legislation, normativity==
:4.1 FDA
:4.2 European normativity