[ Home  |  FAQ-Related Q&As  |  General Q&As  |  Answered Questions ]


    Search the Q&A Archives


please tell me every about polyvinyl alcohol the history,...

<< Back to: Sci.chem FAQ - Part 1 of 7

Question by hoangminh
Submitted on 12/17/2003
Related FAQ: Sci.chem FAQ - Part 1 of 7
Rating: Rate this question: Vote
please tell me every about polyvinyl alcohol
the history, producing , ....
thank you



Answer by crystynai
Submitted on 3/16/2004
Rating:  Rate this answer: Vote
I need all the informations about polyvinyl alcohol. Thank you.

 

Answer by Bendhot
Submitted on 3/10/2005
Rating: Not yet rated Rate this answer: Vote
I need the flow diagram process of the making polyvinyl alcohol from vinyl acetate

 

Answer by Ekele
Submitted on 4/28/2005
Rating: Not yet rated Rate this answer: Vote
a polyvinyl alcohol is a polymer used in degrading plastic products.

 

Answer by Tetê
Submitted on 8/22/2005
Rating: Not yet rated Rate this answer: Vote
I need all the informations about polyvinyl alcohol. Thank you

 

Answer by ishaq
Submitted on 10/3/2005
Rating: Not yet rated Rate this answer: Vote
polyvinyl alcohol resin pva 117 or 217 used in clothes or fiber for strengthness.

 

Answer by paresh
Submitted on 10/8/2005
Rating: Not yet rated Rate this answer: Vote
WHICH ARE THE AVAILABLE GRADE FOR THE FULLY HYDROLYSED GRADE WHICH HAD VISCOSITY 5-7.?

WE SHALL BE THANKFUL TO YOU FOR YOUR KIND INFORMATION

SD- PARESH JASANI

 

Answer by cha
Submitted on 11/22/2005
Rating: Not yet rated Rate this answer: Vote
-It is used as a starting material for the preparation of other resins. It can be used as a component of elastomers used in the manufacture of sponges. This polymer is used in sizing agents that confer resistance to oils and greases upon paper and textiles, to make films resistant to attack by solvents or oxygen. It is used as a component of adhesives, emulsifiers, suspending and thickening agents. In pharcuetical industry, Polyvinyl alcohol is used as a ophthalmic lubricant and viscosity increasing agent. It thickens the natural film of tears in eyes.

 

Answer by freak4science
Submitted on 4/19/2006
Rating: Not yet rated Rate this answer: Vote
well, polyvinyl alcohal is very simple to understand. it is white, has a mild oder and is moderatley souluble. it is stable under normal circumstances. when solid form, has a melting point of 200* C. when combined with sodium tetroborate, it can be made into slime.

 

Answer by PHIPHI
Submitted on 4/27/2006
Rating: Not yet rated Rate this answer: Vote
don't check my spelling you should check yours.

sincerly,
The teacher's Staff

 

Answer by yashar
Submitted on 5/17/2006
Rating: Not yet rated Rate this answer: Vote
I need all the informations about polyvinyl alcohol. Thank you.

 

Answer by aqua
Submitted on 9/27/2006
Rating: Not yet rated Rate this answer: Vote
Preparation:

Unlike most vinyl polymers, PVOH is not prepared by polymerization of the corresponding monomer. The monomer, vinyl alcohol, almost exclusively exists as the tautomeric form, acetaldehyde. PVOH instead is prepared by partial or complete hydrolysis of polyvinyl acetate to remove acetate groups.

-----------------------------------
Properties:

Polyvinyl alcohol has excellent film forming, emulsifying, and adhesive properties. It is also resistant to oil, grease and solvent. PVOH is an atactic material but exhibits crystallinity as the hydroxyl groups are small enough to fit into the lattice without disrupting it. It has high tensile strength, flexibility, as well as high oxygen and aroma barrier. However these properties are dependent on humidity, in other words, with higher humidity more water is absorbed. The water which acts as a plasticiser will then reduce its tensile strength, but increase its elongation and tear strength. PVOH has a melting point of 230°C and 180-190°C for the fully hydrolysed and partially hydrolysed grades. PVOH also decomposes rapidly above 200°C

-------------------------------------------
USES:

Some uses of polyvinyl alcohol include:

   1. Adhesive and thickener material in latex paints, paper   coatings, hairsprays, shampoos and glues.
   2. Carbon dioxide barrier in polyethylene terephthalate (PET) bottles.
   3. Carotid phantoms for use as synthetic vessels in doppler flow testing.
   4. Children's play putty or slime when combined with Borax.
   5. Feminine hygiene and adult incontinence products as a biodegradable plastic backing sheet.
   6. As a mold release because materials such as epoxy do not stick to it.
   7. As a water-soluable film useful for packaging.
   8. As fiber reinforcement in concrete

 

Your answer will be published for anyone to see and rate.  Your answer will not be displayed immediately.  If you'd like to get expert points and benefit from positive ratings, please create a new account or login into an existing account below.


Your name or nickname:
If you'd like to create a new account or access your existing account, put in your password here:
Your answer:

FAQS.ORG reserves the right to edit your answer as to improve its clarity.  By submitting your answer you authorize FAQS.ORG to publish your answer on the WWW without any restrictions. You agree to hold harmless and indemnify FAQS.ORG against any claims, costs, or damages resulting from publishing your answer.

 

FAQS.ORG makes no guarantees as to the accuracy of the posts. Each post is the personal opinion of the poster. These posts are not intended to substitute for medical, tax, legal, investment, accounting, or other professional advice. FAQS.ORG does not endorse any opinion or any product or service mentioned mentioned in these posts.

 

<< Back to: Sci.chem FAQ - Part 1 of 7


[ Home  |  FAQ-Related Q&As  |  General Q&As  |  Answered Questions ]

© 2008 FAQS.ORG. All rights reserved.