Yes, soluble polymers can be used to reduce the pour point of paraffin wax, mainly by changing the formation and aggregation of wax crystals in paraffin wax, thereby improving low-temperature fluidity. The following is a detailed analysis and suggestions:
- Principle: The mechanism of polymers reducing pour point
Soluble polymers as pour point depressants (PPD) have the following mechanisms of action:
Crystal modification: polymers adsorb on the surface of wax crystals to change their crystal morphology, making wax crystals smaller and more irregular, and reducing the mutual aggregation of wax crystals.
Crystal dispersion: The long chain structure of the polymer is compatible with certain parts of the wax molecular chain, thereby reducing the adhesion of wax crystals at low temperatures.
Phase separation delay: inhibit the precipitation temperature of wax from paraffin wax and improve the low-temperature fluidity of the system.
- Applicable soluble polymers
The selection of a suitable polymer should be based on the composition of the paraffin wax (mainly the alkane chain length distribution) and the need for pour point reduction. The following are several common types of polymers:
(1) Polymethacrylate (PMA)
PMA is one of the most commonly used pour point depressants.
It improves its compatibility with paraffin by introducing long-chain alkyl side chains (such as octyl and decyl).
Scope of application: It is suitable for paraffin with high wax content and has a significant effect.
(2) Ethylene-vinyl acetate copolymer (EVA)
EVA has polar groups (vinyl acetate) and non-polar segments (ethylene), which can effectively inhibit the crystallization of long-chain alkanes.
Advantages: It has good dispersion and modification effects on wax crystals and is often used in lubricating oils and fuel oils.
(3) Polyisobutylene (PIB)
PIB is a non-polar polymer that can improve the low-temperature fluidity of paraffin.
Advantages: It has good chemical stability, but the pour point reduction effect may not be as good as PMA and EVA.
(4) Poly-α-olefin copolymer (PAO)
PAO is copolymerized by introducing α-olefin monomers of different chain lengths.
Scope of application: When the requirement for low pour point is high, it can be used in combination with other polymers.
- Precautions for addition and use
Solubility: Soluble polymers must be able to dissolve evenly in paraffin wax to avoid precipitation or precipitation.
Use high temperature (such as 80-100°C) to stir evenly.
Select appropriate solvents (such as benzene, toluene, xylene) as needed.
Addition amount: Generally 0.1%-1% (mass ratio), the specific addition amount needs to be optimized through experiments.
Wax content and chain length: For the alkane distribution of different paraffin waxes, the chain length and polarity of the polymer need to be adjusted to match.
- Experimental verification
In actual use, the depressing effect of the polymer needs to be verified experimentally:
Pour point test: ASTM D97 or similar standards measure the depressing effect.
Low temperature fluidity test: measure dynamic viscosity or low temperature pumping performance.
Compatibility testing: Check whether the polymer will delaminate or precipitate with the paraffin system.
- Alternative methods
If soluble polymers are not effective enough, you can also consider:
Combined additives: Use with other pour point depressants (such as copolymers or surfactants).
Chemical modification: Slightly crack the paraffin or introduce branched chains to reduce wax crystal formation.