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important factor to consider is the variation in temperature
between the day and night, since many materials
are known to act differently in different temperatures. For this
study one concern is that the temperature might drop down below
the glass transition temperature (Tg) of the
natural latex used to create the balloons. Going below the Tg would
cause a definite change in the behavior of the material;
materials above their Tg still retain elasticity,
whereas those cooled below their Tg become
glassy and brittle.22This may cause the
balloon to burst more quickly, especially considering the
pressure and changes of volume the balloon experiences in
its ascent. The Tg value of natural rubber latex is−73◦Celsius.23Since an average day
flight will see temperatures of below−40◦Celsius in the upper troposphere
should night temperatures drop to the range of−65◦Celsius, it is possible that the
natural latex rubber of the weather balloon will experience
temperatures that would cause it to undergo glass
On 3/22/2020 3:29 PM, Joe WB9SBD wrote:
Some evidence, But not totally also.
I wonder how must is lost when the latex is NOT stressed?
Like stretched ONLY to 50% elongation.
We have tension tested many many samples of latex, and it is
amazing on how linear the force is when a piece is being
stretched. From barely stretched to right at the end like 99%
of it's stretchability the forces only change like 10%
But that last bit it the force to pull it any further
skyrockets! ten times or more the rest of the force, and the
amount it continues to stretch is like nothing.
You can even easily feel this by hand. Take a scrap of a
balloon and cut say a 1" wide strip from it. Now start to
pull, the force is more or less the same then it like hit a
brick wall where it does not want to let you stretch any more
then finally breaks.
Hence the flight that lasted two or three days that went from
California to Morocco.
On 3/22/2020 3:16 PM, stan siems
Here is your answer
by DC Handke - 2019
May 1, 2019 - al
(2013) examined the degradation of latex
films in different environments. The degradation
rate was most strongly linked to treatments with the
most solar radiation, causing the fastest rate
of breakdown. Photo-oxidation was the primary pathway
for this degradation. This occurred in
response to UV light from the sun.