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| Addition Polymerization | No small molecule is eliminated during the polymerization process.
Polymer repeating unit contains the same number of atoms as the original
monomer. This polymerization method can be further divided into free
radical addition and ionic polymerizations. These polymerizations occur
by the rapid addition of olefin molecules to an initiated chain end.
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| Agro-energy | Energy generated from agricultural and livestock by-products or
biofuels.
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| Biodiesel | Renewable fuel for diesel engines derived from natural oils such as soybean oil and meeting the specifications of the American Society for Testing and Materials (ASTM).
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| Biofuel | Fuel produced directly or indirectly from biological origin.
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| Biomass | Material of biological origin (excluding material embedded in geological formations and transformed to fossil).
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| Biorefinery | Facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass.
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| Block Copolymer | A polymer
containing a block of one monomer connected to a block of another
monomer. A block copolymer consisting of monomers A and B could be
illustrated as follows. Block polymers are distinguished by the number
of blocks in a single molecule. A-A-A-A-A-A-A-B-B-B-B-B-B-B-B-B-B is a diblock polymer.
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| Chain-growth Polymerization | See Addition Polymerization.
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| Condensation Polymerization | Water or some other simple substance separates from
two or more of the monomer molecules upon their
combination.
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| Contour Length | The length of
the stretched-out molecule. Simplest measure of polymer chain-length.
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| Copolymer | A polymer consisting of
two or more different monomers. The sequence of monomer units along the
polymer chain varies depending on the polymerization method. The three
most common sequence arrangements are random,
regular and block.
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| Graft Copolymer | A polymer resulting from the linkage of two different polymers. This can result from two previously synthesized polymers reacting with each other or the polymerization of a different monomer at initiation sites along the chain of a previously made polymer. A graft copolymer derived from a homopolymer of monomer A and a homopolymer of monomer B can be illustrated as follows. 
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| Hemicellulose |
Polysaccharide, constituting about one-fourth of perennial plants and about one-third of annual plants, that is extractable by dilute alkaline solution. Some examples are:
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| Heterogeneity Index | See Polydispersity Index
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| Heteropolymer | A polymer in which there are sequences or blocks of differing repeating units. |
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| Homopolymer | A polymer is which all
the repeating units are the same.
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| Initiator | Compound that, added in
small quantities, helps to start the polymerization process. Many are
changed during initiation and are therefore not true catalysts.
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| Interesterification | Ester-ester exchange during which the fatty acids of triglycerides
exchange positions from one glyceride to another. Used
industrially to change or control the melting characteristics of oils
and fats.
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| Kraft pulping | A process using an aqueous solution of sodium hydroxide and sodium sulfide to extract lignin from wood fiber source in large chemical digesters. The extracted components are concentrated in a series of evaporators to produce a fuel, black liquor, that is burned in recovery boilers.
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| Lignin | The major organic constituent of wood. Acts as a binder for cellulose fibers and adds strength to cell walls.
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| Lipase | Enzyme that catalyzes the
hydrolysis/esterification of fatty acid bonds. They are produced by
plants, animals, bacteria and molds. Plant enzymes are not used
commercially.
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| Monomer | From Greek word monos,
meaning single. A single unit.
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| Number average degree of polymerization |
( ) - Average number of monomer units per polymer chain.
 measure of extent of reaction or yield
 number of molecules present initially
 number of unreacted molecules at time t.
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| Number average molar mass |
(  ) - The average molar mass of a polymer molecule in a sample of polymer.
 number of molecules having a certain molar mass
 Molar Mass
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| Oligomer | Low weight polymerization
product, usually consisting of only a few monomer units.
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| Oxime | The functional group R=N-OH
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| Polydisperse | Having a
distribution of molar masses.
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| Polydispersity/Heterogeneity index |  or  - A measure of the distribution of molar masses. For an ideal polymer the polydispersity index would equal one. In practice the index is always greater than one due to the distribution of molar masses of real polymers.
 Weight average molar mass
Number average molar mass
 Weight average degree of polymerization
Number average degree of polymerization
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| Polymer | From the Greek words polus, meaning many and meros, meaning parts. Molecules made up of many units.
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| Random Copolymer | A
polymer in
which no specific sequence of the monomer unit is found. A random
copolymer consisting of the monomers A and B could be illustrated as
follows: A-B-B-A-A-A-B-A-B-A-B-B-A-B-A-B
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| Regular Copolymer | A
polymer
containing a regular alternating sequence of monomer units. A regular
copolymer consisting of the monomers A and B could be illustrated as
follows: A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B
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| Step-growth Polymerization | See
Condensation Polymerization.
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| Tall Oil | A mixture of rosin acids and fatty acids obtained as a byproduct in the treatment of pulp. Used in soaps, lubricants, and emulsions.
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| Terpolymer | A polymer containing three different monomer units. Terpolymers can have regular or block sequencing.
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| Weight average degree of polymerization |
( ) -
measure of extent of reaction or yield
number of molecules present initially
number of unreacted molecules at time t
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| Weight average molar mass | (  ) - Takes into account the contribution of mass to the total by different molecules according to their size. Larger or equal to the number average molar mass.
 fraction by weight of molecules having a certain molar mass
 Molar Mass
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| Wood energy | Energy derived from fuelwood, charcoal, forestry residues, black liquor and any other energy derived from trees.
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