To provide a cellulose derivative excellent in thermoplasticity, water resistance and strength (elastic modulus, impact strength), a cellulose derivative, which is obtained by introducing a short-chain organic group (acetyl group), a medium-chain organic group having 3 to 5 carbon atoms and a long-chain organic group having 6 to 30 carbon atoms at the following substitution degrees DSs into a cellulose, is used: Short-chain organic group: 0.7≤DS.sub.SH≤1.5; Medium-chain organic group: 0.5≤DS.sub.ME≤2.0; Long-chain organic group: 0.1≤DS.sub.LO<0.5; and 2.4≤DS.sub.SH+DS.sub.ME+DS.sub.LO≤3.

To provide a cellulose derivative excellent in thermoplasticity, water resistance and strength (elastic modulus, impact strength), a cellulose derivative, which is obtained by introducing a short-chain organic group (acetyl group), a medium-chain organic group having 3 to 5 carbon atoms and a long-chain organic group having 6 to 30 carbon atoms at the following substitution degrees DSs into a cellulose, is used: Short-chain organic group: 0.7≤DS.sub.SH≤1.5; Medium-chain organic group: 0.5≤DS.sub.ME≤2.0; Long-chain organic group: 0.1≤DS.sub.LO<0.5; and 2.4≤DS.sub.SH+DS.sub.ME+DS.sub.LO≤3.

A method is for manufacturing cellulose microfibers in which a problem of yellowing of cellulose microfibers to be obtained was solved, and cellulose microfibers. As to a method for manufacturing cellulose microfibers, cellulose fibers are added with an additive (A) consisting of at least one of a phosphorous acid and a metal phosphite and an additive (B) consisting of at least one of urea and a urea derivative, heated and washed, then fibrillated. Also, as to cellulose microfibers, the fiber width is 1 to 1000 nm, and a part of hydroxy groups of cellulose fibers is substituted with a functional group represented by a predetermined structural formula to introduce an ester of phosphorous acid.

The purpose of the present invention is to provide a cellulose acetate which can be used to obtain an optical film having a very small amount of bright spot foreign matters, with excellent production efficiency, even when cellulose containing a small amount of hemicellulose components and having a high degree of crystallinity is used as a raw material. A cellulose acetate in which a content ratio by mole of mannose units to a sum of xylose units, mannose units and glucose units, which are sugar chain components, is 0.04 mol % or less, and a filtration index K measured by the following measurement method is 30 mL.sup.1 or less. (Measurement method) The cellulose acetate is dissolved in a mixed solvent containing methylene chloride and methanol at a weight ratio of methylene chloride/methanol of 9/1 to obtain a solution with a solid concentration of 16% by weight. The temperature of the solution is adjusted to 25 C., and the solution is subjected to constant-pressure filtration under a pressure of 3 kg/cm.sup.2 using a cloth obtained by stacking three sheets of calico (s 618) (diameter: 15 mm, filtration area: 1.77 cm.sup.2). At this time, the filtration index k (mL.sup.1) is calculated from the following expression, where P.sub.1 represents the amount of filtration (mL) up to 20 minutes after the start of filtration, and P.sub.2 represents the amount of filtration (mL) from 0 to 60 minutes.

The purpose of the present invention is to provide a cellulose acetate which can be used to obtain an optical film having a very small amount of bright spot foreign matters, with excellent production efficiency, even when cellulose containing a small amount of hemicellulose components and having a high degree of crystallinity is used as a raw material. A cellulose acetate in which a content ratio by mole of mannose units to a sum of xylose units, mannose units and glucose units, which are sugar chain components, is 0.04 mol % or less, and a filtration index K measured by the following measurement method is 30 mL.sup.1 or less. (Measurement method) The cellulose acetate is dissolved in a mixed solvent containing methylene chloride and methanol at a weight ratio of methylene chloride/methanol of 9/1 to obtain a solution with a solid concentration of 16% by weight. The temperature of the solution is adjusted to 25 C., and the solution is subjected to constant-pressure filtration under a pressure of 3 kg/cm.sup.2 using a cloth obtained by stacking three sheets of calico (s 618) (diameter: 15 mm, filtration area: 1.77 cm.sup.2). At this time, the filtration index k (mL.sup.1) is calculated from the following expression, where P.sub.1 represents the amount of filtration (mL) up to 20 minutes after the start of filtration, and P.sub.2 represents the amount of filtration (mL) from 0 to 60 minutes.

A reduced energy method produces highly refined cellulose particles from fruit or vegetable mass by providing an initial cellulose mass of particles containing moisture having number average particle diameter of between 0.25 and 1.9 cm and having a moisture content of less than 80% water for the cellulose mass, heating the cellulose mass to between 170 F to less than 212 F to swell and internally shear fiber structure to produce a highly refined cellulose fiber mass having a total dietary fiber (TDF) content greater than 15% as measured by AOAC 991.43 and a water holding capacity greater than three parts water per part fiber as measured by AACC 56-30.

The surface hydrophobization of cellulose nanocrystals (CNCs) by carboxylic acids, biodiesel, or plant oils was conducted via there herein disclosed green process using an one-pot synthetic method. In the process, an aqueous lactic acid syrup served as a solvent to provide a stable and well-dispersed water suspension of CNCs and participated in esterification reactions to produce an intermediate product of polylactic acid (PLA) oligomer grafted CNCs (CNC-g-PLA). This solvent and intermediate product system allows for an in situ solvent exchange from water to lactic acid without prior drying of the CNCs and a subsequent efficient esterification reaction of CNCs with carboxylic acids or esters having a long hydrocarbon chain (FAs). Another advantage of the disclosed process is the ability to reuse the reagents in the subsequent reaction in order to reduce the production cost. Grafting of renewable materials on the surface of CNCs was developed by polyesterification that is capable of being environmentally friendly and mass-produced without any organic solvents or toxic reagents.

The surface hydrophobization of cellulose nanocrystals (CNCs) by carboxylic acids, biodiesel, or plant oils was conducted via there herein disclosed green process using an one-pot synthetic method. In the process, an aqueous lactic acid syrup served as a solvent to provide a stable and well-dispersed water suspension of CNCs and participated in esterification reactions to produce an intermediate product of polylactic acid (PLA) oligomer grafted CNCs (CNC-g-PLA). This solvent and intermediate product system allows for an in situ solvent exchange from water to lactic acid without prior drying of the CNCs and a subsequent efficient esterification reaction of CNCs with carboxylic acids or esters having a long hydrocarbon chain (FAs). Another advantage of the disclosed process is the ability to reuse the reagents in the subsequent reaction in order to reduce the production cost. Grafting of renewable materials on the surface of CNCs was developed by polyesterification that is capable of being environmentally friendly and mass-produced without any organic solvents or toxic reagents.

The present invention describes synthesis and properties of cellulose based biodegradable hydrophobic mulch film for agricultural applications. The invented method can also be used to obtain an highly hydrophobic mulch film. Cellulose, the most abundant natural polymer is chemically modified to make bio-degradable, mulch films that are partially air permeable but water impermeable. The water impermeability can be changed by varying the processing conditions. The film can be multi-functional; that is besides providing the water impermeability the film can also be customized to adjust the pH of soil and to deliver herbicides or fertilizers to the soil. Other lignocellulosic materials or different combinations of synthetic fibers, fabrics or polymers and cellulose materials including newsprint can also be used to make the biodegradable hydrophobic film. Additionally, the invention can be used to make biodegradable extremely hydrophobic self-cleaning products for other hydrophobic applications such as packaging materials or disposable water-proof clothing.

The invention concerns a process for the manufacture of an acylated polymer composition comprising amylose and/or amylopectin, comprising a pre-treatment step in the presence of an acid, a salt and a polycarboxylic acid, subsequent acylation and, preferably, a post-treatment step with an acid. The products obtained are useful as additives in inks, varnishes, lacquers, coatings, thickeners, adhesives or binders.