Acrylic acid

The Merriam-Webster Dictionary has defined Acrylic Acid as:

"an unsaturated liquid acid C3H4O2 that polymerizes readily to form useful products (as constituents for varnishes and lacquers)".

Other names[2]:
1. 2-Propenoic Acid.
2. Glacial acrylic acid.
3. Propene acid
4. Vinylformic Acid.
5. Acroleaic Acid.
6. Ethylene carboxylic acid.

7. Acide acrylique (French). [3]

8. Acido acrilio (Spanish).

9. Kyselina akrylova(Czech).

Properties of Acrylic Acid:

1. Boiling Range is 143 C and m.p. is 13 C. [1]
2. Solubility at 25 C in Water (parts/100) is infinity.
3. Solubility of water at 25 C, (parts/100 monomer) is infinity.
4. Formula of Acrylic acid is CH2=CH-(C=O)-OH.
5. It is a colourless liquid. [2]
6. Its odor is Acrid and odor threshold is 0.1 ppm.
7. Its vapour pressure is 4 mmHg at 20 C.
8. Its refractive index is 1.4224.
9. Its density is 1.049 g/cc at 20 C.

Preparation of Acrylic Acid:[2]
(oxidation) (oxidation)
1: Propylene -----------------> acrolein -----------> Acrylic Acid.

2. Reppe Process:
( nickel halide salt )
Acetylene + Carbon Monoxide + Water ---------------------> Acrylic Acid + H2.

( Hydrolysis )
3. Acrylonitrile ----------------------> Acrylic Acid

Uses of Acrylic Acid: [2]
It is used in the manufacture of certain esters, resins and salts. The polymeric emulsions prepared from Acrylic Acid are used in the coatings for leather, in paints, polishes and adhesives, and in photographic emulsions. It is used for the formation of polyacrylic acid gels, which are a form of polyanionic hydrogels [4].

References:
[1] Encyclopedia of Chemical Processing and Design: Volume 39 - Pollution: Air: Costs: Part 1. Parameters for Sizing Systems to Polymers: Polyamides: Aliphatic
By John J. McKetta, William A. Cunningham

[2] Health Effect Assessments of the Basic Acrylates (Basic Acrylic Monomer Manufacturers Association) by Elizabeth K. Hunt

[3]http://www.chemicalland21.com/industrialchem/functional%20Monomer/ACRYLIC%20ACID.htm#

[4] Encyclopedia of Surface and Colloid Science, Second Edition (Eight-Volume Set) By Ponisseril Somasundaran, Published by CRC Press, 2006, ISBN 0849396050, 9780849396052, 822 pages.

Further Reading:
Acrylic Acid (Environmental Health Criteria)

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Books:
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Carbomer

Carbomer is a type of molecule which is usually obtained by the insertion of Carbon units in a certain molecule. It is a polymer of acrylic acid crosslinked with a polyfunctional molecule or compound such alkyl ethers of sucrose and/or pentaerythritol. [1]

It is also referred to as polyacrylic or polyacrylate.

Types of Carbomers:
In the National Formulary, there are six types of carbomers' monographs:
1. Carbomers 910
2. Carbomers 934
3. Carbomers 934P (The suffix "P" shows that this is a highly purified product and can be used orally). [2]
4. Carbomers 940
5. Carbomers 941
6. Carbomers 1342 [1]

Properties of Carbomers:[2]
1. White powder (Fluffy)
2. Hygroscopic
3. Soluble in water
4. pH of 1% aquous dispersion is 2.5 to 3.0
5. Incompatible with phenol and resorcinol
6. Products of Carbomers are sensitive to light

Uses:
It is mostly used as a suspending agent in Pharmaceutical industry. They are also used as gelling agents at the concentration of 0.5 to 2.0 % in water. [1]

References:
[1]Page # 2444, Encyclopedia of Pharmaceutical Technology by James Swarbrick.

[2] 18.18, Part 4 Pharmaceutical necessities, A Practical Guide to Contemporary Pharmacy Practice by Judith E. Thompson and Lawrence Davidow.

Further Reading:
A Practical Guide to Contemporary Pharmacy Practice by Judith E. Thompson and Lawrence Davidow

The National Formulary X : Tenth Edition

Martindale: The Complete Drug Reference, 35th Edition: Book and CD-ROM Package

Remington: The Science and Practice of Pharmacy

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Macromolecular

Related to molecules having a large molecular mass may be in the range from thousnads to millions.
Biochemically, proteins, lipids, carbohydrates, nucleic acids, polysaccharides are included.

Imbibe

Absorb (water, solution etc.)

Hydrogels

(To study Sphingolipids Click here)

It is also referred to as "Aquagel".

An extremely hydrated polymer gel i.e. colloidal gel giving a jelly like appearance. The polymer chain holds many times its weight in trapped water [1] which can be upto 99%. Hydrogel has water as the dispersion medium or continuous phase.

(N. A. Peppas et al.) Hydrogels resemble, to a large extent, a biological tissue as they are hydrophilic and have the ability to imbibe large amounts of water and other biological fluids. They have a three dimensional macromolecular network. They are insoluble due to chemical and/or physical crosslinking as entaglements and crystallites. The crosslinks are formed by covalent bonds.
Components of hydrogel:
Hydrogel is made by the combination of a hydrophilic component and water i.e.

Hydrogel = Hydrophilic component +  Water

Types:
Hydrogels are
1. natural (Methylcelloluse and agarose)
2. synthetic (Polyacrylamide and polymetha-acrylamide)

(E. Tichy et al.) Two different types of hydrogels:

1. One based on Carbomer.

2. Second based on Polyacrylamide.

Two factors responsible for the extent of swelling and for retaining the water content are as follows:

1. The hydrophilicity of the polymer chain.

2. The crosslinking density. [2]

Properties of Hydrogels:
(Stephen D. Bruck) Properties that can be used to differentiate the hydrogels are

1. Permeability and diffusion co-effecients

2. Some role of quasiorganized water within the hydrogels.

3. Porosity.

4. Presence of functional groups.

5. Types and number of crosslinks.

6. Chemical entities.

Uses:
Hydrogels are very absorbent in nature.
They are also used in sustained release drug delivery systems.

References:
[1]http://www.nature.com/nrmicro/journal/v2/n2/glossary/nrmicro821_glossary.html

[2] 7.2, Engineering Materials For Biomedical Applications (Biomaterials Engineering and Processing Series) by Teoh Swee Hin

E. Tichy, Z. Vitkova, B. Cupkova, Effect of beta-(1,3)-glucan on rheological properties and stability of topical formulations. Die Pharmazie, 2006 Dec;61(12): Pages 1050-1.

N. A. Peppas, P. Bures, W. Leobandung and H. Ichikawa, Hydrogels in pharmaceutical formulations. European Journal of Pharmaceutics and Biopharmaceutics , Volume 50, Issue 1, 3 July 2000, Pages 27-46

Stephen D. Bruck, Aspects of three types of hydrogels for biomedical applications. Journal of Biomedical Materials Research(Volumes 1-23), Volume 7 Issue 5, Pages 387 - 404

Further Reading:
Biodegradable Hydrogels for Drug Delivery by Haesun Park, Kinam Park and Waleed S. W. Shalaby

Hydrogels and Biodegradable Polymers for Bioapplications (Acs Symposium Series, 627) by Raphael M. Ottenbrite, Samuel J. Huang and Kinam Park

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Medicine

A substance used to cure a disease or any other disturbance in the body.