The gas bubbles have helped the material for 3D printing to expand 40 times

American
chemists have developed a new expanding
material
for 3D printing.
Products
of a material increase
in size
on
4000
percent

for this it is sufficient to heat them to 200
degrees Celsius. Extension
occurs under the action of small
bubbles of carbon dioxide produced
of di-tert-of BUTYLCARBAMATE,
which
add to the source material before
print. Results
research published
in the journal ACS
Applied Materials & Interfaces.

With
using 3D printing can be quickly and
cheap to create the most
different
objects
high
level of detail
choice
print media is also very
wide.
One
of the few restrictions remains
the size of the resulting product is normally not
maybe
the size of the used
printer. Large
objects usually
printed
in parts
not
only increases the time of their creation,
but also affects the mechanical
properties
final
products.

American
chemists under the leadership of Jonathan
Pokorski (Jonathan
K. Pokorski) from
University of California, San Diego
developed
new material for 3D printing
products which can expand
when
heated.
Scientists
experimented with cheap
3D printer
Anycubic Photon,
which
works on the principle of laser
stereolithography.
It
one
of the most common ways
3D printing
in
which
new layers of the polymer hardens under
laser
radiation.
Stereolithography
allows
to print
quickly, however
restricts user choice
material
to print:
it
should contain a component
which
quickly
polimerizuet under the influence
laser.

According to
to the authors, the expansion of the material
is due
small bubbles of gas
are formed throughout the volume of the finished
of the product when it is heated to
a certain temperature.
Expanding
material needs
include
three components: Foundation
future
polymer (prepolymer),
photoinitiator,
which
reacts
the inclusion of the laser
and runs
the polymerization process
in
printing and
gazoobraznogo
component
which
in
the right moment will turn into bubbles
gas and
ensure
the extension is ready
products.
Below
all
worked according to the plan,
you need
to fulfill several conditions.
First,
gas-forming
component well to dissolve
in a liquid prepolymer, or
the case in the finished product blowing
component
will
distributed
unevenly,
and when you extend
the shape of the product may
distorted.
Secondly, the temperature
the collapse of the gas-forming
substances should
lie
in the interval between the temperature
glass transition
and
melting point
the obtained polymer — or at
heated the finished product it is not
increase in the amount and melt.
Third,
the polymer should contain a small
the number of cross-linkers —
special binders
groups
which
help the polymer to heal
in
quick time
extensions
the action of the gas bubbles.
Fourth
condition adds
use Anycubic
Photon: the
this 3D printer
not the most powerful laser
(1 mW/cm2),
so
for
the foundations of the desired polymer,
for
hardening of which is such
power.

In
search for the perfect formula, the authors
tested
two options
prepolymer,
three
option
the photoinitiator
and six variants
gas-forming
component
by combining them in different
combinations
and proportions
— all
tested
73
samples of different composition.
In
in the end
as the basis of the material chosen
2-hydroxyethyl methacrylate
(HEMA),
to him
added ten mass percent
di-tert-BUTYLCARBAMATE of (BOC2O),
which
when heated decomposes to isobutylene,
tert-butanol and carbon dioxide. The
effective photoinitiator was
a mixture of two derivatives of phosphine oxide
— BAPO
and
TPO.
Ready
the product was heated to 200 degrees Celsius
within 10 minutes (the temperature of dissolution
BOC2O),
and they gradually increased in volume.
The authors were able to increase
volume of product in 4000
percent
(in
40 times)

this is two orders of magnitude greater than the results
previous studies.
When
this form and proportion of the goods remained
very close to the original.

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