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Difference between revisions of "Polymerisation"
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==Feedstock== | ==Feedstock== | ||
=== Origin and composition === | === Origin and composition === | ||
Several bio-based feedstock options have been explored for the production of bio-based polymers. Lignin can be depolymerised and the obtained products can be used as monomers. Ethanol from fermentations can be processed to produce ethylene, a common feedstock for polymerisations. Fatty acids can be used in long-chain linear aliphatic polymers. Other biomass feedstock includes CO<sub>2</sub>, terpenes, and furfural.<ref name=":0">{{Cite journal|title=Sustainable polymers from biomass: Bridging chemistry with materials and processing|year=2020-02-01|journal=Progress in Polymer Science|volume=101|page=101197|doi=10.1016/j.progpolymsci.2019.101197|author=Zhongkai Wang, Mitra S. Ganewatta, Chuanbing Tang}}</ref> | Several bio-based feedstock options have been explored for the production of bio-based polymers. Lignin can be depolymerised and the obtained products can be used as monomers. Ethanol from fermentations can be processed to produce ethylene, a common feedstock for polymerisations. Fatty acids can be used in long-chain linear aliphatic polymers. Other biomass feedstock includes CO<sub>2</sub>, terpenes, and furfural.<ref name=":0">{{Cite journal|title=Sustainable polymers from biomass: Bridging chemistry with materials and processing|year=2020-02-01|journal=Progress in Polymer Science|volume=101|page=101197|doi=10.1016/j.progpolymsci.2019.101197|author=Zhongkai Wang, Mitra S. Ganewatta, Chuanbing Tang}}</ref> | ||
=== Pre-treatment === | === Pre-treatment === | ||
The pre-treatment of the feedstock for polymerisation is depending on the specific process and feedstock used. In principal, the feedstock is converted to a building block like ethylene, propylene, styrene or others in a first step and then polymerised in a catalytic process. High purity of the feedstock is crucial for successful polymerisation reactions, which are highly susceptible to pollutants, often leading to lower polymerisation grades or smaller polymerisation chains. | |||
==Process and technologies== | ==Process and technologies== | ||
There has been signifcant effort to produce polymers from biomass rest streams. The key challenge lies in producing materials that have comparable or improved properties to their fossil-based counterparts. The right processing, which is often neglected by chemists, plays a crucial role in enhancing the material properties.<ref name=":0" /> | [[File:Polystyrene formation.PNG|thumb|right|400px|An example of '''alkene polymerization''', in which each [[styrene]] monomer's double bond reforms as a single bond plus a bond to another styrene monomer. The product is [[polystyrene]].]] | ||
There has been signifcant effort to produce polymers from biomass rest streams. The key challenge lies in producing materials that have comparable or improved properties to their fossil-based counterparts. The right processing, which is often neglected by chemists, plays a crucial role in enhancing the material properties.<ref name=":0" /> The specific technologies are depending on the types of polymer, but normally do not differ from conventional polymerisation processes in case of drop-in polymers like bio-based PE, PP, PET and others. | |||
:[[File:PLA from lactic acid & lactide.png|300px|Two main routes to PLA]] | |||
==Product== | ==Product== | ||
Three critical processes to obtain sustainable bio-based polymers are the conversion of lignin monomers to polymers, the production of bio-based polyolefins, for example from ethylene via the ethanol route, and the production of long-chain aliphatic polycondensates, which can be obtained from fatty acids.<ref name=":0" /> | Three critical processes to obtain sustainable bio-based polymers are the conversion of lignin monomers to polymers, the production of bio-based polyolefins, for example from ethylene via the ethanol route, and the production of long-chain aliphatic polycondensates, which can be obtained from fatty acids.<ref name=":0" /> | ||
=== Post-treatment === | === Post-treatment === | ||
Normally the resulting polymers are compounded to plastics with different kinds of additives like plasticizers or others or post-processed to reach their aimed properties. In case of plastics the material normally is melted and extruded to pellets for the further processing. | |||
==Technology providers== | ==Technology providers== | ||