i need to get water vapour transmission rate of polymer, i have find different equations in research paper?what is actual eqation?initial and final weight(of cup is 15.708 and 15.553)....anybody plz help to get water vapour transmission rate so that i can do all other films
procedure i used to find wvtr
Bottles with 1.5cm mouth diameter were taken and filled with 10ml deionized water. The mouth of the bottle was covered with polymer film and was covered using Teflon tape. The bottle was weighed and placed in an oven for 24hrs at 40oC . . After 24hrs the bottle was taken out of the oven and weighed again. WVT can be calculated
Hi;
The water vapor permeability was calculated using the following equation:
WVP = P . x/t . A P0 (RH1 - RH2)
where P/ t is the change in the film weight (g/h) which was determined as the slope of the plot of weight loss as a function of time, x the film thickness (mm), A the film cross-sectional area (m2), P0 is the pressure of pure water vapor (KPa), and (RH1–RH2) is the relative humidity gradient. The value of P0 at 25 °C is 3.159 KPa.
With my best regards
To calculate WVTR, Apply this general equation:-
WVTR = G × 24/T.A.
'G' represents change in weight, 'T' is time (measured in hours during which the weight loss occurred), and 'A' is the exposed area of the film
The water vapor transmission rate (WVTR) can be calculated using the following equation:
WVTR = (dM/dt) / (A * ΔP)
Where: WVTR is the water vapor transmission rate (in units such as g/m²/day or g/m²/hr). dM/dt is the mass of water vapor transmitted through the material (in grams) per unit time (in days or hours). A is the surface area of the material through which the vapor is transmitted (in square meters). ΔP is the partial pressure difference of water vapor across the material (in units such as Pa or mmHg).
Please note that the specific equation and units may vary depending on the standards or methods used for measuring WVTR. Different testing methods, such as gravimetric or instrumental methods, may have their own specific equations and units for WVTR calculation.
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