Design,Preparation And Applications Of Biobased Functional Polymers Derived From Small Molecule Biomasses

Biobased polymers are the polymers derived from renewable natural resources.The use of biobased polymers can avoid the dependence of polymers on unrenewable fossil resources and reduce carbon emissions.Therefore,the development of biobased polymers has gathered a lot of interest.Biobased polymers can be classified into two major categories:natural polymers(cellulose,lignin,etc.)and synthetic biobased polymers which are obtained via the polymerization of natural small molecules.Natural polymers are plentiful in the world.However,their properties are deeply influenced by source and meanwhile their chemical structures are complex,which go against the design and development of polymeric materials.As compared with natural polymers,natural small molecules have a wealth of sources and categories,clear chemical structures and properties.Therefore,natural small molecules can be regarded as the substitutes of unrenewable fossil derivatives.In the present study,natural small molecules were used as raw materials to prepare biobased functional polymers.Such biobased functional polymers with specific morphologies including polymeric microspheres,hollow particles and porous monoliths,were prepared via precipitation polymerization or template methods.Constructing biobased polymers with specific morphologies can promote the application potentials of biobased polymers and expand the application fields of biobased polymers.Constructing biobased polymers with specific functions can upgrade biobased polymers into high value-added materials,thereby realizing a win-win situation in both sustainable materials and economy.This work not only enriched the types and preparation methods of biobased functional polymers,but also provided ideas for developing new application fields of biobased functional polymers.The main research contents are as follows:1.A typical biobased ?-methylstyrene derivative,trans-anethole(ANE)was used as raw material to prepare biobased heat-resistant copolymeric microspheres via precipitation polymerization.The morphology and size distribution of the microspheres were characterized by SEM.By adjusting the experimental conditions,including the ratio of good solvent/poor solvent,initiator concentration and monomer ratio,the optimal polymerization conditions were obtained.Under the optimal polymerization conditions,the growth of microspheres was investigated by following the microsphere formation process and thereby a possible mechanism for precipitation polymerization was proposed.The chemical structure of the microspheres was investigated by FT-IR and NMR and the results indicated that the microspheres were constructed by alternating copolymers.TGA and DSC demonstrated the remarkable thermal stability of the microspheres.2.A typical biobased ?-methylstyrene derivative,methyl isoeugenol(MeIE)was used as raw material to copolymerize with maleic anhydride(MAH)to prepare poly(MeIE-co-MAH)microspheres via precipitation polymerization.The morphology and size distribution of the microspheres were characterized by SEM.By adjusting the experimental conditions,including the ratio of good solvent/poor solvent,initiator concentration,monomer ratio and polymerization time,the optimal polymerization conditions were obtained.Crosslinking agent divinylbenzene(DVB)was added in the polymerization system under the optimal polymerization condition to prepare crosslinked microspheres.The obtained crosslinked microspheres further underwent hydrolyzation to transform anhydride groups to carboxylic groups.The newly-formed hydrolyzed microspheres showed remarkable adsorption towards metal ions(with Cu2+ as representative,up to 300 mg/g).Thereby,the unprecedented microspheres are expected to find practical applications,e.g.,as green adsorbents in wastewater treatment.3.Biomass ferulic acid was used as raw material to prepare biobased monomer 4VGMA.Then the obtained 4VGMA was used as crosslinking agent to copolymerize with MAH to form biobased hollow polymer particles(BHPs)via hard-template method.After consecutive reaction with ethylenediamine and HCl,the prepared BHPs were transformed to ammonium-functionalized BHPs(BHP-NH3+).The transformation process was qualitatively and quantitatively characterized by FT-IR,XPS and elemental analysis.The density of ammonium group in BHP-NH3+was about 3.1 mmol/g.The prepared BHP-NH3+could be further served as high-performance selective adsorbent for removal methyl orange(MO),a model anionic dye from water.The maximum adsorption capacity of BHP-NH3+to MO was 952 mg/g,and the selective adsorption mechanism was electrostatic interaction.Desorption experiments demonstrated that the desorption process could be facilely and efficiently realized by adjusting the solution pH,and recycle tests indicated that the particles exhibited remarkable recyclability.4.Hollow polymer particles(HPPs)constructed by biomass trans-anethole and maleic anhydride were firstly reacted with propargylamine to form hollow particles simultaneously bearing carboxyl groups and polymerizable alkynyl groups(named as M-HPPs).Then the obtained M-HPPs were further copolymerized with a chiral acetylenic monomer to prepare hollow particles grafted with chirally helical polymer chains.Circular dichroism(CD)and UV-vis absorption spectra indicated that the hollow particles grafted with chirally helical polymer chains exhibited considerable optical activity.The optically active hollow particles were demonstrated enantioselectivity in adsorption quinoline-type chiral drugs.Such enantioselectivity was provided by synergistic effects between stereo-selective and electrostatic interactions between chiral drugs and optically active hollow particles.5.Biomass lactides were used as raw material to prepare chirally helical polylactides bearing polymerizable vinyl group via ring-open polymerization.Then the obtained polylactides were employed as macro-monomers to copolymerize with vinyl monomers through high internal phase emulsion(HIPE)polymerization,fabricating chiral porous polyHIPEs.The pore structures of the polyHIPEs were qualitatively and quantitatively characterized by SEM and mercury intrusion porosimetry measurement.The optical activity of polyHIPEs was characterized by CD and UV-vis spectroscopies.Cytotoxicity tests demonstrated that the different chirality of polylactides exerted different effects on cell growth.Release tests demonstrated that only the polyHIPE constructed by PLLA exhibited the anticipated enantioselectivity.