How does one calculate the molecular weight of entanglements of an ultra high molecular weight glassy polymer?

Some viscoelastic analysis indicated that the ultra high molecular weight PVAc homo polymer may contains physical cross linking due to the entanglements. How can i calculate the mol wt of the...

07 August 2014 6,813 6 View

Is there any model to study the thermal conductivity/heat conduction in multilayer foam/film systems?

Currently, I am working with a system that is basically assemblies of alternating solid and porous polymeric layers (figure is attached). I am interested to study the thermal conductivity of such...

01 February 2014 10,004 3 View

How to measure the total reflection of a film?

Currently, I am looking for a way to measure the total reflection of a reflective film. I am using an UV instrument equipped with a reflection mode and it measures the absolute reflection of the...

08 September 2013 5,235 5 View

Can anyone give an example of a natural material which is porous but transparent? Or has a layered porous structure?

I am looking for the example of a natural material that has a multilayered porous structure and is optically transparent.

04 May 2013 1,554 19 View

Is reversible hydrogen bonding possible in epoxidized natural rubber (ENR)?

ENR posses high polar group contents possibly due to the random epoxidation of polyisoprene backbones. Partial ring opening of epoxide group can contribute to OH group formation and thus able to...

10 November 2012 9,589 2 View

What is the chemical/structural origin of stickiness in Epoxidized natural rubber?

Inspite of having higher Tg, Epoxidized natural rubber (with 25 and 50 mol% epoxidation level) exhibit higher stickiness than the synthetic polyisoprene (cis). Why?

08 September 2012 9,707 2 View

Looking for Materials with high thermal expansion coefficient and high temperature resistance?

03 March 2021 8,272 1 View

Polymer composites suddenly solidifies?

I am making polymer composite by solvent mixing method. When I am trying to add filler solution in polymer solution it quickly get solidified. How to make them then uinform? It doesn't give time...

03 March 2021 7,540 4 View

How the parameters (such as Mw, Chemical bonds, polymer bland and so on) affect the mechanic property of polymer (such as storage, loss modulus) ?

Anyone can recommend any books on such topics? Thanks in advance.

02 March 2021 8,457 2 View

How do I determine the degree of polymerization of PEG 400 based on NMR integration?

Hello, I am working on the photocatalytic degradation of PEG 400. I would like to know if it's possible to determine the degree on polymerization based on NMR integration, or by the MW of the...

02 March 2021 6,186 3 View

How to polymerize TEOS?

I want to polymerize TEOS on a surface. I know that NH4OH is a preferred catalyst and an alcoholic solvent should be used .But I can not find certain amounts of each material to use. Does any one...

02 March 2021 1,404 6 View

What are anisotropic electrical and optical properties of a semiconductor due to?

In some materials, properties such as band gap, thermal conductivity differ along different crystallographic axes. What are the basics?

01 March 2021 1,923 3 View

Can polymer concentrations be calculated based on the number average molecular weight?

Hello, I spin-cast two different polymers onto wafers and measure their height as a function of initial concentration. For polymer A, I have the weight-average molecular weight (Mw) as well as...

28 February 2021 7,882 2 View

Problem with shRNA transfection. Why are only two plates getting contaminated instead of all?

I transfected my LNCaP-WT cells with 3 shRNA plus their NTC two weeks ago and split two puromycin selected cell plates on Friday last week(Feb 26). I checked for GFP in the cells, and they all...

28 February 2021 4,949 3 View

1 nm thick MgO thin-film to be deposited on Si wafer using thermal evaporation. What will be the optimum deposition conditions?

Favourable conditions of base pressure, rate of deposition. Also, by which characterisation technique to be used to verify the thickness of the deposited film.

28 February 2021 3,640 3 View

POlymer+DMSO solution and moisture??

What could be the reason of moisture at the sides of Vial when I am preparing my polmyer+DMSO solution for membrane fabrication? What etiquettes I am possibly missing here?

28 February 2021 6,516 5 View