Acyclic diene metathesis with a monomer from renewable resources: control of molecular weight and one-step preparation of block copolymers

Synthesis of Polyesters Containing Long Aliphatic Methylene Units by ADMET Polymerization and Synthesis of ABA-Triblock Copolymers by One-Pot End Modification and Subsequent Living Ring-Opening Polymerization

The synthesis of high-molecular-weight (Mn up to 62,000 g/mol) polyesters has been achieved by acyclic diene metathesis (ADMET) polymerization of α,ω-dienes prepared from biobased bis(undec-10-enoate) and diols [ethylene glycol (M1), propylene glycol (M2), 1,9-nonanediol (M3), 1,4-benzenedimethanol (M4), and hydroquinone (M5)] using ruthenium-carbene catalysts. Replacement of the solvent during the ADMET polymerization was effective for obtainment of the high-molecular-weight polymers (expressed as P1-P5). The melting temperatures (Tm) in the resultant polyesters were dependent upon the diol (middle) segment employed, and the polymer prepared from M5 exceeded 100 °C (a Tm value of 122.5 °C). The polymerization of M3 and M4 in the presence of 1,4-cis-diacetoxy-2-butene (DAB, as the chain transfer agent) afforded the telechelic polyesters [P3(OAc)2 and P4(OAc)2, respectively] containing acetoxy end groups exclusively. The resultant polymers containing hydroxy group termini [P3(OH)2 and P4(OH)2], prepared by the selective deprotection of the acetoxy end groups, were treated with AlEt3 followed by addition of ε-caprolactone to afford the ABA-type triblock copolymers exclusively, through a living ring-opening polymerization. The depolymerization (hydrolysis) under basic conditions (NaOH aqueous solution) of P3 was explored.

Synthesis of Network Biobased Aliphatic Polyesters Exhibiting Better Tensile Properties than the Linear Polymers by ADMET Polymerization in the Presence of Glycerol Tris(undec-10-enoate)

Development of biobased aliphatic polyesters with better mechanical (tensile) properties in film has attracted considerable attention. This report presents the synthesis of soluble network biobased aliphatic polyesters by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enyl)isosorbide diester [M1, dianhydro-D-glucityl bis(undec-10-enoate)] in the presence of a tri-arm crosslinker [CL, glycerol tris(undec-10-enoate)] using a ruthenium-carbene catalyst, and subsequent olefin hydrogenation using RhCl(PPh3)3. The resultant polymers, after hydrogenation (expressed as HCP1) and prepared in the presence of 1.0 mol% CL, showed better tensile properties than the linear polymer (HP1) with similar molecular weight [tensile strength (elongation at break): 20.8 MPa (282%) in HP1 vs. 35.4 MPa (572%) in HCP1]. It turned out that the polymer films prepared by the addition of CL during the polymerization (expressed as a 2-step approach) showed better tensile properties. The resultant polymer film also shows better tensile properties than the conventional polyolefins such as linear high density polyethylene, polypropylene, and low density polyethylene.

Synthesis of High Molecular Weight Biobased Aliphatic Polyesters Exhibiting Tensile Properties Beyond Polyethylene

Synthesis of high molecular weight polyesters prepared by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enoate) with isosorbide (M1), isomannide (M2), and 1,3-propanediol (M3) and the subsequent hydrogenation have been achieved by using a molybdenum-alkylidene catalyst. The resultant polymers (P1) prepared by the ADMET polymerization of M1 (in toluene at 25 °C) possessed high Mn values (Mn = 44400-49400 g/mol), and no significant differences in the Mn values and the PDI (Mw/Mn) values were observed in the samples after the hydrogenation. Both the tensile strength and the elongation at break in the hydrogenated polymers from M1 (HP1) increased upon increasing the molar mass, and the sample with an Mn value of 48200 exhibited better tensile properties (tensile strength of 39.7 MPa, elongation at break of 436%) than conventional polyethylene, polypropylene, as well as polyester containing C18 alkyl chains. The tensile properties were affected by the diol segment employed, whereas HP2 showed a similar property to HP1.

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids

Acyclic diene metathesis (ADMET) polymerization of an α,ω-diene monomer of bis(undec-10-enoate) with isosorbide (M1) using a RuCl₂(IMesH₂)(CH-2-O ⁱ Pr-C₆H₄) (HG2, IMesH₂ = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) catalyst and conducted at 50 °C (in vacuo) in ionic liquids (ILs) afforded higher-molecular-weight polymers (P1, M _n = 32 200-39 200) than those reported previously (M _n = 5600-14700). 1-n-Butyl-3-methyl imidazolium hexafluorophosphate ([Bmim]PF₆) and 1-n-hexyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)imide ([Hmim]TFSI) were suitable as effective solvents among a series of imidazolium salts and the pyridinium salts. The polymerization of α,ω-diene monomers of bis(undec-10-enoate) with isomannide (M2), 1,4-cyclohexanedimethanol (M3), and 1,4-butanediol (M4) in [Bmim]PF₆ and [Hmim]TFSI also afforded the higher-molecular-weight polymers. The M _n values in the resultant polymers did not decrease even under the scale-up conditions (300 mg to 1.0 g scale, M1, M2, and M4) in the polymerizations in [Hmim]TFSI; the subsequent reaction of P1 with ethylene (0.8 MPa, 50 °C, and 5 h) gave oligomers (proceeded via depolymerization). Tandem hydrogenation of the resultant unsaturated polymers (P1) in a [Bmim]PF₆-toluene biphasic system upon the addition of Al₂O₃ (1.0 MPa H₂ at 50 °C) gave the corresponding saturated polymers (HP1), which waswere isolated by a phase separation in the toluene layer. The [Bmim]PF₆ layer containing the ruthenium catalyst could be recycled without a decrease in the activity/selectivity of the olefin hydrogenation at least eight times.

Synthesis of Semicrystalline Long Chain Aliphatic Polyesters by ADMET Copolymerization of Dianhydro-D-glucityl bis(undec-10-enoate) with 1,9-Decadiene and Tandem Hydrogenation

Acyclic diene metathesis (ADMET) copolymerization of dianhydro-D-glucityl bis(undec-10-enoate) (M1) with 1,9-decadiene (DCD) using ruthenium-carbene catalyst, RuCl2(IMesH2)(CH-2-OiPr-C6H4) [IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene, HG2], afforded unsaturated polyesters (Mn = 9300–23,400) under the optimized conditions. Subsequent tandem hydrogenation (H2 1.0 MPa, 50 °C) with the addition of a small amount of Al2O3 resulted in the saturated polymers having a melting temperature of 71.7–107.6 °C, depending on the molar ratio of M1 and DCD.

Plant oil-based polymers

Polymer materials derived from natural resources have gained increasing attention in recent years because of the uncertainties concerning petroleum supply and prices in the future as well as their environmental pollution problems. As one of the most abundant renewable resources, plant oils are suitable starting materials for polymers because of their low cost, the rich chemistry that their triglyceride structure provides, and their potential biodegradability. This chapter covers the structure, modification of triglycerides and their derivatives as well as synthesis of polymers therefrom. The remarkable advances during the last two decades in organic synthesis using plant oils and the basic oleochemicals derived from them are selectively reported and updated. Various methods, such as condensation, radical/cationic polymerization, metathesis procedure, and living polymerization, have also been applied in constructing oil-based polymers. Based on the advance of these changes, traditional polymers such as polyamides, polyesters, and epoxy resins have been renewed. Partial oil-based polymers have already been applied in some industrial areas and recent developments in this field offer promising new opportunities.

Synthesis of Biobased Long-Chain Polyesters by Acyclic Diene Metathesis Polymerization and Tandem Hydrogenation and Depolymerization with Ethylene

Acyclic diene metathesis (ADMET) polymerization of biobased α,ω-dienes of bis(undec-10-enoate) with diols (1,4-butanediol, isosorbide, isomannide, and 1,4-cyclohexanedimethanol) afforded high-molecular weight unsaturated polyesters, and subsequent tandem hydrogenation (H2 1.0 MPa, 50 °C, 3 h) gave the saturated polymers upon addition of a small amount of Al2O3 (1.0-1.7 wt %). Subsequent reaction of the unsaturated polymers with ethylene afforded the oligomers (by depolymerization and degradation).

Polymers from sugars and unsaturated fatty acids: ADMET polymerisation of monomers derived from d-xylose, d-mannose and castor oil

High molecular weight renewable polyesters are synthesised from an unsaturated fatty acid and structurally unmodified, hemicellulosic sugars, with post-polymerisation modification inducing semicrystallinity and allowing casting of transparent films.

Synthesis of new polyesters by acyclic diene metathesis polymerization of bio-based α,ω-dienes prepared from eugenol and castor oil (undecenoate)

Synthesis of high molecular weight polymers by acyclic diene metathesis (ADMET) polymerization of α,ω-diene prepared from bio-renewable eugenol and castor oil (undecenoate) has been demonstrated.

Macrocycle-based topological azo-polymers: facile synthesis and unusual photoresponsive properties

Macrocycle-based topological azo-polymers with unusual photosensitive properties were synthesized via a selective acyclic diene metathesis polymerization of different monomers using an acrylate-functionalized cyclic azo-polymer as a chain stopper prepared from a linear precursor by “click” cyclization reaction, which will open a new perspective in photoinduced materials.

Bio-Based Polymers with Potential for Biodegradability

A variety of renewable starting materials, such as sugars and polysaccharides, vegetable oils, lignin, pine resin derivatives, and proteins, have so far been investigated for the preparation of bio-based polymers. Among the various sources of bio-based feedstock, vegetable oils are one of the most widely used starting materials in the polymer industry due to their easy availability, low toxicity, and relative low cost. Another bio-based plastic of great interest is poly(lactic acid) (PLA), widely used in multiple commercial applications nowadays. There is an intrinsic expectation that bio-based polymers are also biodegradable, but in reality there is no guarantee that polymers prepared from biorenewable feedstock exhibit significant or relevant biodegradability. Biodegradability studies are therefore crucial in order to assess the long-term environmental impact of such materials. This review presents a brief overview of the different classes of bio-based polymers, with a strong focus on vegetable oil-derived resins and PLA. An entire section is dedicated to a discussion of the literature addressing the biodegradability of bio-based polymers.

Renewability is not Enough: Recent Advances in the Sustainable Synthesis of Biomass-Derived Monomers and Polymers

Taking advantage of the structural diversity of different biomass resources, recent efforts were directed towards the synthesis of renewable monomers and polymers, either for the substitution of petroleum-based resources or for the design of novel polymers. Not only the use of biomass, but also the development of sustainable chemical approaches is a crucial aspect for the production of sustainable materials. This review discusses the recent examples of chemical modifications and polymerizations of abundant biomass resources with a clear focus on the sustainability of the described processes. Topics such as synthetic methodology, catalysis, and development of new solvent systems or greener alternative reagents are addressed. The chemistry of vegetable oil derivatives, terpenes, lignin, carbohydrates, and sugar-based platform chemicals was selected to highlight the trends in the active field of a sustainable use of renewable resources.

Green chain-shattering polymers based on a self-immolative azobenzene motif

A chain-shattering polymer system consisting of nontoxic, partially renewable resource-based monomersviaacyclic diene metathesis (ADMET) chemistry is introduced.

ADMET and TAD chemistry: a sustainable alliance

Post-polymerisation functionalisation and subsequent crosslinking of unsaturated ADMET derived polymers were performed via the versatile and ultrafast 1,2,4-triazoline-3,5-dione click chemistry.

Sustainable Polyesters Derived from Glucose and Castor Oil: Building Block Structure Impacts Properties

Using the glucose derivatives isosorbide and glucarodilactone along with a castor oil derivative, 10-undecenoyl chloride, two monomers were synthesized: glucarodilactone undecenoate (GDLU) and isosorbide undecenoate (IU). These monomers were polymerized via acyclic diene metathesis (ADMET) polymerization to yield two homopolymers, P(GDLU) and P(IU), and two copolymers, P₁(GDLU-co-IU) and P₂(GDLU-co-IU), of similar number-averaged molecular weight and relative composition (51 and 61 kDa, Đ = 1.8 and 1.4, 46:54 and 52:48 mol percent). Comparison of the physical properties and degradation behavior of these polymers revealed divergent characteristics arising from differences in the nature of the carbohydrate building blocks. P(IU) is more thermally stable and has a lower glass transition temperature (T_d = 369 °C, T_g = -10 °C) than P(GDLU) (T_d = 206 °C, T_g = 32 °C) and P_1,2(GDLU-co-IU) (T_d = 210 and 203 °C, T_g = 1 and 7 °C). While all of the polymers were stable in acidic and neutral aqueous conditions, the two analogs containing GDLU hydrolytically degraded in the presence of base. Tensile testing of the systems revealed that both homopolymers are brittle materials while the P(GDLU-co-IU) is more tough. Notably, P_1,2(GDLU-co-IU) was found to be a rubbery material with a low Young's modulus (0.020 and 0.002 GPa, respectively), displaying an average elongation at break of 480 and 640%, and shape memory properties.

ADMET polymerization of bio-based biphenyl compounds

Bio-based phenols were dimerized and employed as monomers in ADMET polymerization.

Biobased building blocks for the rational design of renewable block polymers

Block polymers (BPs) derived from biomass (biobased) are necessary components of a sustainable future that relies minimally on petroleum-based plastics for applications ranging from thermoplastic elastomers and pressure-sensitive adhesives to blend compatibilizers. To facilitate their adoption, renewable BPs must be affordable, durable, processable, versatile, and reasonably benign. Their desirability further depends on the relative sustainability of the renewable resources and the methods employed in the monomer and polymer syntheses. Various strategies allow these BPs' characteristics to be tuned and enhanced for commercial applications, and many of these techniques also can be applied to manipulate the wide-ranging mechanical and thermal properties of biobased and self-assembling block polymers. From feedstock to application, this review article highlights promising renewable BPs, plus their material and assembly properties, in support of de novo design strategies that could revolutionize material sustainability.

Star-shaped polyphosphoesters with reactive end groups synthesized via acyclic diene metathesis polymerization and their transformation to nanostructures

Four-arm star shaped polyphosphoesters are synthesized via acyclic diene metathesis (ADMET) polymerization.

Functional α,ω-dienes via thiol-Michael chemistry: synthesis, oxidative protection, acyclic diene metathesis (ADMET) polymerization and radical thiol–ene modification

The synthesis of the novel α,ω-diene 2-(undec-10-en-1-yl)tridec-12-en-1-yl acrylate is described.

Renewable polyesters derived from 10-undecenoic acid and vanillic acid with versatile properties

A series of renewable polyesters were synthesized derived from 10-undecenoic acid and vanillic acid. An outstanding feature is that the incorporation of vanillic acid segments into the polyester backbone results in improved mechanical properties.

Convenient divergent synthesis of linear-dendron block polyphosphoesters via acyclic diene metathesis polymerization

ADMET polymerization was successfully applied for the synthesis of linear-dendritic polyphosphoester structures by using macromolecular chain stoppers.