HDPE with NBR blending modification of what kind of?
HDPE with NBR blending modification of what kind of?
High density polyethylene)
The impact strength is not high, on the purpose has been curbed.
At present, with nonpolar elastomer modified situation more.
Polar elastomer (
Nitrile silicone containing polar groups cyano, good oil resistance, heat resistance, water resistance, etc. , differ with HDPE solubility parameter, belong to the thermodynamic incompatible system, but the reasonable process conditions, can make its good process compatibility.
A small amount of NBR can greatly improve the impact strength of HDPE, and the morphology of filamentous parallel arrangement.
Because of HDPE and NBR for incompatible system need to join the compatilizer.
Related products: thermoplastic epdm products)
Was prepared by melt blending of HDPE/NBR binary blend and HDPE/NBR/HDPE -
MAH three yuan, a total of kunduz, the results show that the binary blending system with different polarity, add 15% of NBR can get the impact strength of 712.
2 j/m, morphology of parallel arrangement of filamentous blend;
To add a compatilizer HDPE -
MAH ternary blending system, the impact strength of 845.
9 j/m, adding compatilizer toughening effect after improved.
Compatilizer HDPE -
MAH molecules directly compatible with HDPE, HDPE parts of MAH section containing carbonyl groups of polarity, chemical reaction with the NBR of acrylonitrile to generate hydrogen bond.
With both ends respectively two components compatible with HDPE, NBR, it have the effect of the emulsifier, reduces the phase interface, and add two bonding force, formed a stable phase dispersion structure, make the dispersed phase particles are dispersed in a continuous phase, effectively improve the compatibility of the two components, so as to improve the impact toughness.
According to the compatilizer compatibilizing mechanism analysis, to join the more compatible dose, modification effect should be better, but the experiment proved that adding 10% compatilizer instead, there is no 5% compatilizer modification effect is good.
May be because the compatilizer fill in multiphase interface between blending system, make the polyphase interfacial macromolecular chain segment by compatibilizers and mutual infiltration, diffusion, and it could reduce the interface energy, increase the force and effect.
Only when the compatilizer on the phase interface is right amount, compatibilizing effect is best.
With polarity NBR modified nonpolar HDPE, the modification effect with NBR grades, content and HDPE melt flow rate of the polymer matrix, mixing time, and process conditions, such as temperature, roll away.
In began to join the NBR, the impact strength of blending system into a linear increase.
When the content of NBR reaches a certain value, the impact strength reached maximum.
Since then, with the increase of content of NBR, the impact strength was worse instead.
Modification effect is better than NBR - 18
By the principle of 'similarity', the more similar the polarity of the plastic and silicone rubber facies, the better the compatibility.
So of HDPE/NBR -
18 the compatibility of blend is better than that of HDPE/NBR -
The modification effects of different type of HDPE order for: 8900 s & gt;
Three grades of HDPE melt flow rate of the size order for: 5070 ea & gt;
The influence of process conditions on the impact strength is very large.
Mixing time, shear strength is appropriate, required by the system viscosity can be close to blend ideal viscosity.
Mixing at low temperature, due to the melt viscosity is too high, the dispersed phase and continuous phase is difficult to spread out, from the macro and micro mixing between silicon rubber and the matrix resin is not easy to achieve;
While the temperature is too high, greatly reduced the viscosity of the melt, this also make the viscosity of dispersed phase and continuous phase difference is big, silicone rubber particles regrouped, lower toughness.
In addition, high temperature silicone rubber is easy to heat air oxidation degradation, also affect performance.
Reflect the size of the shear strength of the size of the roller spacing, roller spacing, the greater the shearing action of the material is smaller;
Roller spacing is smaller, the greater the shearing action of the material.
To a certain extent, the size of the roller spacing is consistent with the length of the mixing time.
Relevant process recommended: the advantages and disadvantages of all kinds of silicone rubber roller and craft formula introduced melt blending of HDPE/NBR blend, belong to pseudoplastic fluid, viscosity, with the increase of shear rate and temperature and lower, with the decreasing of NBR and compatibilizer content decreases.
Under the condition of different ratio, T = 190 ℃, when NBR content intact, its apparent viscosity increased with the increase of content of compatibilizer.
As compatibilizers in HDPE and NBR with two phase interface between physics, chemistry, the HDPE molecule chains and NBR molecular chain to form entanglement, enhance the interaction between HDPE and NBR, hindered the normal flow of molecular chain and lead to blend melt motion in the flow resistance increases, the apparent viscosity of blending system increased.
More information about HDPE and NBR, please continue to pay attention: rubber products factory.
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