Plant waxes are the protective cover between the plant cells and their environment, by which they regulate their water loss, and protect themselves from the environment.

When we speak of plant waxes, it is usually as if it were a single compound, but a deeper look reveals that it is a mixture of simple Alkanes, Alcohols, Aldehydes, and Fatty Acids, ranging from 20 carbon chains, to about 34. 

To put them into perspective, the well known Carnauba (C30 H62 O)  and Candelilla (C31 H64 O) plant waxes are C-30 and C-31 molecules respectively.  About the same consistency as bees wax, and denser than (C16 H34 O) ear wax.

WAXES
WaxAlcoholFatty Acid
CarnaubaCH3(CH2)28CH2-OHCH3(CH2)24COOH
BeeswaxCH3(CH2)28CH2-OHCH3(CH2)14COOH
Spermacetic (ear wax)CH3(CH2)14CH2-OHCH3(CH2)14COOH
   

 I’ve not found an analysis of cannabis plant waxes, but looking at plant waxes in general, here is a breakdown of what is in the waxes from the leaves of the xxxx plant, giving perspective as to the mixture:

% of Fraction in Plant Waxes from:http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00581.x/full
CarbonAlkanesAlcoholsAldehydesFatty Acids
201
21tr
22tr2
23tr1
24127
25trtr2
26Tr335
275144
283132419
2947488
304333131
31384
322282821
3323
347
Total72912
Tr = Traces less than 0.5% undetectable

 Notice that it is no longer an issue of non polar plant waxes, as only the Alkane molecules are non polar.

Molecular weights also become an issue, when you are talking about processes like SCFE CO2, where molecular weights above about 400 g/mol are mostly insoluble.

Looking at C-30 Carnauba wax for instance as  CH3(CH2)28CH2OH or simplified as  C30H62O, it has a molecular weight of about  438.8127 g/mol.  http://www.webqc.org/molecular-weight-of-CH3%28CH2%2928CH2OH.html

SymbolElementAtomic WtAtomsTotal
CCarbon12.010730360.321
HHydrogen1.007946262.49228
OOxygen15.9994115.9994
Molecular Weight   438.81268 g/mol

 That suggests of course that those molecules smaller than about C-27 will have a molecular weight below 400 g/mol, so are readily extracted by SCFE CO2 as well.

Here are some interesting reads on plant waxes:

Biology of the plant cuticle:

https://books.google.com/books?id=qaJVSVYZhVQC&pg=PA119&lpg=PA119&dq=cannabis+plant+wax+chemical+properties&source=bl&ots=UUTo76r1TW&sig=HHQ6RLAXHETfeB5SIHLx8Wnh4b4&hl=en&sa=X&ved=0ahUKEwjbv5uOk7nXAhVDylQKHcBTCLEQ6AEIcjAO#v=onepage&q=cannabis%20plant%20wax%20chemical%20properties&f=false

Leaf cuticular waxes are arranged in chemically and mechanically distinct layers: evidence from Prunus laurocerasus L.

http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00581.x/full

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