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Most unmodified polymers such as rigid PVC, PMMA, PS, or SAN are brittle materials
at ambient temperature. Even pseudo-ductile engineering polymers, such as PC,
PA, or PE, will exhibit a brittle-to-ductile transition temperature and limited
impact strength.
In consequence, most polymers have to be impact modified in order to satisfy
end-use requirements for rigid applications. In all cases, the problem can be
solved by incorporating rubber domains into the polymer matrix. However, the
nature and the size of the elastomeric phase has to be adapted to each polymer
matrix. In most cases, it is also desirable to use the minimum amount of rubber
modifier, in order not to affect optical, rheological and physical properties (such as modulus).
The most important characteristics of an impact modifier are :
- The rubber glass transition temperature
- The rubber domain particle size in the matrix
- The quality of dispersion
- The adhesion to the polymer matrix
Among the families of plastic tougheners, MBS core-shell impact modifier
can be used in materials like PVC and some engineering polymers. MBS are used
in most of transparent applications not requiring weather resistance. Moreover, they are particularly
efficient for low temperature impact performances. Some grades are suitable for opaque
applications.
Another efficient family of Acrylic
core-shell impact modifiers provides also excellent performance in outdoor
applications.
We propose the following items to aid product development requiring impact performance
with MBS:
An introduction
where most toughening technologies will be described.
The definition of
core shell impact modifier.
The basic toughening
mechanism
The Benefits of MBS
as impact modifiers
Applications
of MBS impact modifiers in rigid PVC formulation for market such as bottles,
films and pipes & fittings.
If you need fast and efficient assistance for your problems with
impact modification of PVC, use TechDirect,
our free technical assistance service provided with the help of an expert in this field.
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