Cellulose nanocrystals (CNCs) were modified with natural di- and tricarboxylic acids using two concurrent acid-catalyzed reactions including hydrolysis of amorphous cellulose segments Fischer esterification, resulting in the introduction free carboxylic acid functionality onto CNC surfaces. esterification was characterized by Fourier transform infrared spectroscopy, 13C solid state magic-angle spinning (MAS), conductometric titration experiments. Average degree substitution values for...

A general protocol for the rhodium-catalyzed oxidative carbonylation of arenes to form esters has been developed. broad substrate scope demonstrated allowing electron-rich, electron-poor, and heterocyclic arenes, reaction shows wide functional group tolerance excellent regioselectivities. Up 96% yield ortho-substituted aryl or heteroaryl carboxylic were obtained with this methodology. The possible mechanism was proposed in article. Studies show that Oxone play an important role transformation.

A series of biobased epoxy monomers were prepared from diphenolic acid (DPA) by transforming the free into n-alkyl esters and phenolic hydroxyl groups diglycidyl ethers. NMR experiments confirmed that ethers diphenolates (DGEDP) with methyl ethyl have 6 3 mol % glycidyl ester. Increasing chain length DGEDP to n-pentyl resulted in large decreases resin viscosity (700-to-11 Pa·s). Storage modulus DPA resins, cured isophorone diamine, also varied ester (e.g., 3300 2100 MPa for esters). The...

Despite attractive properties of cellulose nanocrystals (CNCs) such as high natural abundance, inherent biodegradability and modulus, CNCs tend to degrade aggregate when exposed temperatures during melt processing. In the present work, surface was modified with PMMA take advantage miscibility various biobased polymers including PLLA melt-blended. Particular attention paid grafting techniques in water medium using two different redox initiators: Fe2+/H2O2 (Fenton's reagent) ceric ammonium...

Poly(pentadecalactone)-b-poly(l-lactide) (PPDL-b-PLLA) diblock copolymers were prepared via the organic catalyzed ring-opening polymerization (ROP) of l-lactide (l-LA) from PPDL macroinitiators using either 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). Synthesis PLLA blocks targeting degrees (DP) up to 500 found yield with crystalline and segments when TBD was used as catalyst. The synthesis further improved in a one-pot, two-step process same...

A green manufacturing technique, reactive extrusion (REx), was employed to improve the mechanical properties of polylactide (PLA). To achieve this goal, a fully biosourced PLA based polymer blend conceived by incorporating small quantities poly(ω-hydroxytetradecanoic acid) (PC14). PLA/PC14 blends were compatibilized transesterification reactions promoted 200 ppm titanium tetrabutoxide (Ti(OBu)4) during REx. REx for 15 min at 150 rpm and °C resulted in enhanced while minimizing losses...

Enzyme catalysed ring-opening polymerisation was performed by reactive extrusion gave high molecular weight polyester (<italic>M</italic>_w ≥ 163 000 g mol⁻¹) in 15 minutes.

Poly(ε-caprolactone) (PCL) is a ductile thermoplastic, which biodegradable in the marine environment. Limitations include low strength, petroleum-based origin, and comparably high cost. Cellulose fiber reinforcement therefore of interest although uniform dispersion challenge. In this study, one-step wet compounding proposed to validate sustainable feasible method improve cellulose fibers hydrophobic polymer matrix as PCL, showed be insensitive presence water during processing. A comparison...

A series of nanocomposites were prepared from graphene platelets (GPL) and a flexible biobased epoxy thermoset matrix derived cashew nut shell liquid. The loading GPL in the ranged 0.1 to 0.8 wt % resulted increased tensile strength Young's modulus (17 33 MPa 474 1700 MPa, respectively). Increases mode I fracture toughness for KIC GIC 0.6 1.9 MPa·m1/2 906 1734 J/m2, respectively. Furthermore, dynamic mechanical analysis revealed that incorporation increases α-transition temperature (peak...

With the combinations of diglycidyl ether diphenolate methyl ester (DGEDP-Me), a rigid high-viscosity bio-based epoxy resin and flexible lower viscosity from cashew nut shell liquid (NC-514), was controlled important improvements were realized in cured toughness relative to neat resins. The viscosities DGEDP-Me/NC-514 mixtures varied 660 26 Pa.s, curing performed using stoichiometric amounts diamine cross-linker. Using scanning electron microscopy analysis fractured surfaces, materials shown...

Adding nucleating agents (NAs) is one of the most efficient ways to obtain improved mechanical, optical, and thermal properties isotactic polypropylene (iPP). While it well appreciated that electrical property critically affected by crystalline modification, role between them remains unclear. Here, we address this issue incorporating commercial α-NA β-NA into iPP, both which exhibit strong nucleation ability, e.g., reducing size agglomerates from 45.3 μm (Pure-iPP) 2.5 (α-iPP) 7.6 (β-iPP),...

A convenient synthetic method was reported for the preparation of N-phthaloyl dehydroamino acid esters from easily accessible vinyl bromides (or tosylate) and potassium phthalimide. Rh-catalyzed asymmetric hydrogenation these substrates with TangPhos gave products good to excellent enantioselectivities (up 99% ee).

Polylactide (PLA) is a commercially produced bio-based thermoplastic with unique properties such as high strength, biocompatibility and biodegradability. However, the low heat deflection temperature (HDT) of PLA significantly impedes its industrial implementation for high-performance applications, requiring design PLA-based nanocomposites.Cellulose nanocrystals (CNCs) are derived from cellulose which highly abundant in nature, non-toxic, biodegradable, has density. CNCs possess many...

Modified cellulose nanocrystals were decorated with silver nanoparticles using a one-pot reduction method. In contrast to quasi-uniform distribution of nanoparticles, we report on the interactions non-contact nanoparticle clusters significant line broadening and red shifts in extinction spectra. The particle size cluster distributions examined transmission electron microscope. Monte Carlo random walk (MCRW) simulations spectrum show that interacting nanospheres are organized small, clusters....

Using highly electron-rich monophosphine ligands, Suzuki­ cross-coupling of heteroaromatic chlorides with various boronic­ acids was carried out in high yields. High yields were also often observed when steric employed Suzuki reactions.

Connective tissue extracellular matrix (ECM) consists of an interwoven network contiguous collagen fibers that regulate cell activity, direct biological function, and guide homeostasis throughout life. Recently, ECM analogs have emerged as a unique ex vivo culture platform for studying healthy diseased tissues in the latter, enabling screening development therapeutic regimen. Since these models can mitigate concern observations from animal do not always translate clinically, design...

We discuss some optical properties of cellulose nanocrystals decorated with silver nanospheres. give a short description the discrete dipole interactions, and broadening effects observed in extinction spectrum. also preliminary results for their use organic photovoltaic devices.

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