POLYMER ENGINEERING - QUESTION 24.1 : The molecular weights M in kg / mol of 3 different monomers a, b and c in a polymer are Ma = 14, Mb = 16 and Mc = 18. The fraction of polymer chain X of 3 different monomers a, b and c in a polymer are Xa = 0.5, Xb = 0.3 and Xc = 0.2. (i) Calculate number average molecular weight by using the formula Ma Xa + Mb Xb + Mc Xc. (ii) Calculate weight average molecular weight by using the formula (Ma Xa Ma + Mb Xb Mb + Mc Xc Mc) / (Ma Xa + Mb Xb + Mc Xc). (iii) Calculate the polydispersity by using the answer in (ii) divided by answer in (i). (iv) If the molecular weight of repeat unit is 12, calculate the degree of polymerization by using the formula (Ma Xa + Mb Xb + Mc Xc) / (molecular weight of repeat unit).

Answer Posted / kangchuentat

POLYMER ENGINEERING - ANSWER 24.1 : (i) Number average molecular weight = Ma Xa + Mb Xb + Mc Xc = 14 x 0.5 + 16 x 0.3 + 18 x 0.2 = 15.4 kg / mol. (ii) Weight average molecular weight = (Ma Xa Ma + Mb Xb Mb + Mc Xc Mc) / (Ma Xa + Mb Xb + Mc Xc) = (14 x 0.5 x 14 + 16 x 0.3 x 16 + 18 x 0.2 x 18) / 15.4 = 15.558 kg / mol. (iii) Polydispersity = [ answer in (ii) ] / [ answer in (i) ] = 15.558 / 15.4 = 1.0103. (iv) Degree of polymerization = (Ma Xa + Mb Xb + Mc Xc) / (molecular weight of repeat unit) = (15.4 kg / mol) / (12 g / mol) = 1.283 k = 1283. The answer is given by Kang Chuen Tat; PO Box 6263, Dandenong, Victoria VIC 3175, Australia; SMS +61405421706; chuentat@hotmail.com; http://kangchuentat.wordpress.com.

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How can you control the ph level in our cooling water with respect to ammonia contamination?

703


What is the purpose of capacitor?

1575


How can hexavalent chromium be removed from aqueous waste streams?

714


PLZ ANYONE SEND ME PLACEMENT PAPERS OF I.O.C.L MY ID---- gaurav.nitw.5609@gmailcom

2200


What type of pump may be appropriate for a liquid near saturation, a low flow rate, and very limited npsha (net positive suction head available)?

731






I am a Diploma Chemical Engineer by Nirma Uni; and BEng (Hons) Energy & Environmental Engineer by Napier Uni; Edinburg, UK. HPCL chemical engineering test will held on 14th July,09. So, Please send me some previous chemical engineering papers Objective types Or material to give the test.

3154


Is there any way to repair a valve that is passing leaking internally without taking our process offline?

816


What is screen analysis?

824


which materials can l use if l want to use length wave 680 to 900 in hplc

1662


hi i need cpcl written exam question papers if anybody pls help me

5628


Can asphalt be recycled to form a useful product?

719


How fouling effected the heat transfer rate?

782


Hi, I am Gurunathan. I am in need of ONGC, IOCL, DRDO technical test ( chemical engineering)and general aptitude questions. If anyone has kindly post it to me soon.

2427


What are the methods involved to test helium leak testing in a vacuum system?

763


What is pneumatic conveying?

807