Combination and processing keratin with lignin as biocomposite materials for additive manufacturing technology.

Additive manufacturing using Nature's resources is a desirable goal. In this work we examine how the inherent macromolecular properties of keratin and lignin can be utilised and developed using green chemistry principles to form 4D functional materials. A new methodology utilising protein complexation by lignin was applied to form copolymers and reinforce keratin cross-linking networks on aqueous and solid state processing. Solubility, chemical and processing characteristics found a favoured 4:1 ratio of keratin to lignin was most desired for effective further processing as 3D printed paste forms. Thermally processing keratin-lignin with plasticisers and processing aids demonstrated extruded FDM filaments could be formed at temperatures >130°C, but degradation of keratin-lignin materials was observed. Employing paste printing strategies, keratin-lignin hydrogels could successfully print 3D skirt outlines. This was achieved with aqueous hydrogels prepared at 30-40% solids content with and without plasticizers over a defined processing timeframe. Mechanical response to moisture stimuli was successfully demonstrated for the 4:1 keratin-lignin printed material on water soaking, realising the ability of these keratin-lignin biocomposite materials to introduce a 4th dimensional response after 3D printing. STATEMENT OF SIGNIFICANCE: In this paper we describe new perspectives for how biopolymers can be used and processed to develop (co)polymers as 3D & 4D printed responsive materials without the need for synthetic chemical modifications. We utilise a novel methodology employing bioconjugation to synthesise and develop co-polymer materials from keratin and lignin and demonstrate this can be achieved in both water and solid state. We manipulate the inherent chemical attributes of both biopolymers to develop these new functional materials under green chemistry processing conditions. This is a practical example how the chemical coupling of two biopolymers at molecular-scale can be leveraged to give co-polymer materials which retain their inherent macromolecular properties to behave as functional, 4D responsive biomaterials.

Synchrotron-based X-ray fluorescence microscopy in conjunction with nanoindentation to study molecular-scale interactions of phenol-formaldehyde in wood cell walls.

Understanding and controlling molecular-scale interactions between adhesives and wood polymers are critical to accelerate the development of improved adhesives for advanced wood-based materials. The submicrometer resolution of synchrotron-based X-ray fluorescence microscopy (XFM) was found capable of mapping and quantifying infiltration of Br-labeled phenol-formaldehyde (BrPF) into wood cell walls. Cell wall infiltration of five BrPF adhesives with different average molecular weights (MWs) was mapped. Nanoindentation on the same cell walls was performed to assess the effects of BrPF infiltration on cell wall hygromechanical properties. For the same amount of weight uptake, lower MW BrPF adhesives were found to be more effective at decreasing moisture-induced mechanical softening. This greater effectiveness of lower MW phenolic adhesives likely resulted from their ability to more intimately associate with water sorption sites in the wood polymers. Evidence also suggests that a BrPF interpenetrating polymer network (IPN) formed within the wood polymers, which might also decrease moisture sorption by mechanically restraining wood polymers during swelling.

Vegetable oil thermosets reinforced by tannin-lipid formulations.

Totally bio-based thermosetting polymers which are comparable to synthetic polyester thermosets have been prepared from copolymerization of condensed tannin-fatty acid esters with vegetable oils. Oxidative copolymerization of tannin linoleate/acetate mixed esters with linseed oil and tung oil produced polymer films ranging from soft rubbers to rigid thermosets. Tannin incorporation into the formulations was essential for the final product to achieve necessary mechanical strength. Films had ambient modulus values between 0.12 and 1.6 GPa, with glass transition temperatures ranging from 32 to 72 °C and calculated crosslink densities of 1020-57,700 mol m⁻³. Film stiffness, T(g) and crosslink density increase with greater tannin linoeate/acetate content due mainly to this tannin component providing rigidity through polyphenolic aromatic rings and unsaturated chains as crosslinking sites.

Production, composition and toxicology studies of Enzogenol® Pinus radiata bark extract.

Enzogenol® pine bark extract is a dietary supplement and food ingredient produced by water extraction of Pinus radiata. We present production method, composition, and safety data from rat and dog toxicological and human clinical studies. The dry powder contains proanthocyanidins (>80%), taxifolin (1-2%), other flavonoids and phenolic acids (up to 8%), and carbohydrates (5-10%). Reverse mutation assays showed lack of mutagenic activity. Single and 14-day repeat dosing in rats and dogs had no influence on body weight, feed consumption, blood chemistry, and haematology at any dose level. There were no treatment related findings on gross and detailed necroscopy, organ weights, organ weight ratios and histology. The only adverse events were emesis and diarrhoea in dogs occurring mainly in un-fed condition and at the highest dose level in a total of 18% of applications. The MTD and NOAEL in the present rat and dog studies were 2500 and 750 mg/kg/day, respectively. Consumption of 480 mg/day for 6 months and 960 mg/day for 5 weeks in two human studies showed Enzogenol® had no adverse influence on liver and kidney function, haematology, and did not cause any adverse events. Our studies indicate lack of toxicity of Enzogenol® and support safe use as a food ingredient.

Synthesis and Characterization of Sterically Encumbered Derivatives of Aluminum Hydrides and Halides: Assessment of Steric Properties of Bulky Terphenyl Ligands.

The synthesis and characterization of several sterically encumbered monoterphenyl derivatives of aluminum halides and aluminum hydrides are described. These compounds are [2,6-Mes(2)C(6)H(3)AlH(3)LiOEt(2)](n)() (1), (Mes = 2,4,6-Me(3)C(6)H(2)-), 2,6-Mes(2)C(6)H(3)AlH(2)OEt(2) (2), [2,6-Mes(2)C(6)H(3)AlH(2)](2) (3), 2,6-Mes(2)C(6)H(3)AlCl(2)OEt(2) (4), [2,6-Mes(2)C(6)H(3)AlCl(3)LiOEt(2)](n)() (5), [2,6-Mes(2)C(6)H(3)AlCl(2)](2) (6), TriphAlBr(2)OEt(2) (7), (Triph = 2,4,6-Ph(3)C(6)H(2)-), [2,6-Trip(2)C(6)H(3)AlH(3)LiOEt(2)](2) (8) (Trip = 2,4,6-i-Pr(3)C(6)H(2)-), 2,6-Trip(2)C(6)H(3)AlH(2)OEt(2) (9), [2,6-Trip(2)C(6)H(3)AlH(2)](2) (10), 2,6-Trip(2)C(6)H(3)AlCl(2)OEt(2) (11), and the partially hydrolyzed derivative [2,6-Trip(2)C(6)H(3)Al(Cl)(0.68)(H)(0.32)(&mgr;-OH)](2).2C(6)H(6) (12). The structures of 2, 3a, 4, 6, 7, 9a, 10a, 10b, 11, and 12 were determined by X-ray crystallography. The structures of 3a, 9a, 10a, and 10b, are related to 3, 9, and 10, respectively, by partial occupation of chloride or hydride by hydroxide. The compounds were also characterized by (1)H, (13)C, (7)Li, and (27)Al NMR and IR spectroscopy. The major conclusions from the experimental data are that a single ortho terphenyl substituent of the kind reported here are not as effective as the ligand Mes (Mes = 2,4,6-t-Bu(3)C(6)H(2)-) in preventing further coordination and/or aggregation involving the aluminum centers. In effect, one terphenyl ligand is not as successful as a Mes substituent in masking the metal through agostic and/or steric effects.

Imide Transfer Properties and Reactions of the Magnesium Imide ((THF)MgNPh)(6): A Versatile Synthetic Reagent.

Imide transfer properties of ((THF)MgNPh)(6) (1) and the synthesis of the related species {(THF)MgN(1-naphthyl)}(6).2.25THF (2), via the reaction of dibutylmagnesium with H(2)N(1-naphthyl), in a THF/heptane mixture are described. Treatment of 1 with Ph(2)CO, 4-Me(2)NC(6)H(4)NO, t-BuNBr(2) (3), PCl(3), or MesPCl(2) (Mes = 2,4,6-Me(3)C(6)H(2)-) leads to the isolation of Ph(2)CNPh (4), 4-Me(2)NC(6)H(4)NNPh (5), t-BuNNPh (6), (PhNPCl)(2) (7), or (MesPNPh)(2) (8) in moderate yield. Reaction between 1 and GeCl(2).dioxane, SnCl(2), or PbCl(2) affords the M(4)N(4) (M = Ge, Sn, Pb) cubane imide derivative (GeNPh)(4) (9), [(SnNPh)(4).{MgCl(2)(THF)(4)}](infinity) (10), (SnNPh)(4).0.5PhMe (11), or (PbNPh)(4).0.5PhMe (12). Interaction of 1 with Ph(3)PO, (Me(2)N)(3)PO, or Ph(2)SO furnishes the complex (Ph(3)POMgNPh)(6) (13), {(Me(2)N)(3)POMgNPh}(6).2PhMe (14), or (Ph(2)SOMgNPh)(6) (15). The addition of 3 equiv of MgBr(2) to 1 gives 1.5 equiv of ((THF)Mg)(6)(NPh)(4)Br(4) (16) in quantitative yield, whereas treatment of 16 with 4 equiv of 1,4-dioxane is an alternative synthetic route to 1. Compounds 2, 3, 9, 10, and 14 were characterized by X-ray crystallography. The reactions demonstrate that 1 is a versatile and useful reagent for the synthesis of a variety of main group imides. Crystal data at 130 K with Mo Kalpha (lambda = 0.710 73 Å) radiation for 3 or Cu Kalpha (lambda = 1.541 78 Å) radiation for 2, 9, 10, and 14: 2, C(93)H(108)Mg(6)N(6)O(7.25), a = 28.101(7) Å, b = 35.851(7) Å, c = 36.816(7) Å, Z = 2, space group Fddd, R = 0.068 for 3500 (I > 2sigma(I)) data; 3, C(4)H(9)Br(2)N, a = 6.682(2) Å, b = 10.834(3) Å, c = 11.080(3) Å, alpha = 66.25(2) degrees, beta = 89.88(2) degrees, gamma = 82.53(2) degrees, Z = 4, space group P&onemacr;, R = 0.038 for 2043 (I > 2sigma(I)) data; 9, C(24)H(20)Ge(4)N(4), a = 10.749(2) Å, b = 12.358(3) Å, c = 35.818(7) Å, Z = 8, space group Pbca, R = 0.040 for 2981 (I > 2sigma(I)) data; 10, C(40)H(52)Cl(2)MgN(4)O(4)Sn(4), a = 12.770(3) Å, b = 13.554(3) Å, c = 25.839(5) Å, Z = 4, space group P2(1)2(1)2(1), R = 0.040 for (I > 2sigma(I)) data; 14, C(86)H(154)Mg(6)N(4)O(6)P(6), a = 22.478(4) Å, b = 16.339(3) Å, c = 29.387(6) Å, Z = 4, space group Pbcn, R = 0.081 for 4696 (I >2sigma(I)) data.