Biocomposite material

Abstract

A biocomposite material ( 1 ) and methods of production thereof are described. The biocomposite material ( 1 ) exhibits a physical stiffness, strength and toughness comparable to known glass fibre composites while its composition makes it inherently impermeable to water. A general formulation for the biocomposite material ( 1 ) is given by the expression: Cel (1-x-y) HPI x HPO y where “Cel” represents cellulose fragments ( 2 ), “HPI” represents hydrophilic binders ( 4 ), “HPO” represents hydrophobic binders ( 5 ) and (x) and (y) quantify the percentage by weight of the hydrophilic ( 4 ) and hydrophobic binders ( 5 ) present within a material, respectively. The described properties of the biocomposite material ( 1 ) are achieved when (x) is within the range of from 0.05 to 0.55 and (y) is within the range of from 0.05 to 0.65.

1 . A method for producing cellulose fragments comprising a network of cellulose microfibrils, the method comprising:
 treating a plant material to obtain a first pulp of the plant material;   mixing the first pulp with a bleach solution so that a quantity of pectins and hemicelluloses present within the plant material are dissolved within a resultant solution;   producing a second pulp by removing the bleach from the resultant solution; and   reducing the water content present within the second pulp.   
     
     
         2 . The method of  claim 1 , wherein the step of treating the plant material comprises:
 heating the plant material to obtain a softened plant material;   blending the softened plant material with water to obtain a blended resultant residue; and   adding a micro-organism to the blended resultant residue to aid the breakdown of the plant material.   
     
     
         3 . The method of  claim 2 , further comprising filtering any resultant liquid from the softened plant material. 
     
     
         4 . The method of  claim 2 , wherein the micro-organism is bacterium or yeast. 
     
     
         5 . The method of  claim 1 , wherein the step of producing a second pulp comprises homogenising the resultant solution and then washing and filtering the homogenised resultant solution to remove the bleach. 
     
     
         6 . The method of  claim 1 , wherein the step of reducing the water content present within the second pulp results in the second pulp comprising at least 40% water by weight. 
     
     
         7 . A method for producing a biocomposite material comprising:
 producing a plurality of cellulose fragments, comprising a network of cellulose microfibrils;   incorporating a hydrophilic binder within the network of cellulose microfibrils; and   encapsulating the plurality of cellulose fragments within a hydrophobic binder.   
     
     
         8 . The method of  claim 7 , wherein the step of producing the plurality cellulose fragments comprises:
 treating a plant material to obtain a first pulp of the plant material;   mixing the first pulp with a bleach solution so that a quantity of pectins and hemicelluloses present within the plant material are dissolved within a resultant solution;   producing a second pulp by removing the bleach from the resultant solution; and   reducing the water content present within the second pulp.   
     
     
         9 . The method of  claim 7 , wherein the step of incorporating the hydrophilic binder within the network of cellulose microfibrils comprises:
 re-hydrating the cellulose fragments with the hydrophilic binder and water so as to produce a paste; and   removing excess water and excess hydrophilic binder from the paste.   
     
     
         10 . The method of  claim 9 , wherein the re-hydrating step comprises re-hydrating the cellulose fragments with a first emulsion comprising the hydrophilic binder so as to produce a paste. 
     
     
         11 . The method of  claim 7 , wherein the step of encapsulating the plurality of cellulose fragments comprises:
 mixing the hydrophobic binder and the paste containing the hydrophilic binder so as to produce a composite paste material;   removing water from the paste material; and   curing the dried paste material.   
     
     
         12 . The method of  claim 11 , wherein the step of encapsulating the plurality of cellulose fragments further comprises
 Applying pressure to the paste material.   
     
     
         13 . The method of  claim 12 , wherein the mixing step further comprises
 producing a second emulsion comprising the hydrophobic binder; and   mixing the second emulsion and the paste containing the hydrophilic binder so as to produce a composite paste material.   
     
     
         14 . The method of  claim 13 , wherein the production of the second emulsion involves mixing the hydrophobic binder with a surfactant and water. 
     
     
         15 . The method of  claim 14 , wherein the surfactant is non-ionic. 
     
     
         16 . The method of  claim 13 , wherein the production of the second emulsion comprises:
 obtaining a sample of individual cellulose fibrils and microfibrils derived from the plant material; and   mixing the hydrophobic binder with the sample.   
     
     
         17 . The method of  claim 16 , wherein the sample of individual cellulose fibrils and microfibrils derived from the plant material is obtained from a method comprising:
 producing a first pulp of the plant material;   mixing a first pulp with a bleach solution so that a quantity of pectins and hemicelluloses present within the plant material are dissolved within a resultant solution;   producing a second pulp by removing the bleach from the resultant solution; and   homogenising the second pulp so as to reduce the cellulose in the second pulp to individual cellulose fibrils and microfibrils.   
     
     
         18 . The method of  claim 17 , wherein the sample of individual cellulose fibrils and microfibrils derived from the plant material is obtained from a method comprising:
 producing a first pulp of the plant material;   mixing a first pulp with a bleach solution so that a quantity of pectins and hemicelluloses present within the plant material are dissolved within a resultant solution;   homogenising the resultant solution so as to reduce the cellulose in the second pulp to individual cellulose fibrils and microfibrils; and   removing the bleach from the homogenised solution.   
     
     
         19 . The method of  claim 17 , wherein the homogenising is carried out using high shear mixing. 
     
     
         20 . The method of  claim 17 , wherein the homogenising is carried out using high pressure homogenisation up to 1000 bar. 
     
     
         21 . The method of  claim 11 , wherein the homogenising is carried out using high pressure homogenisation up to 1000 bar. 
     
     
         22 . The method of  claim 11 , comprising a method of obtaining a sample of individual cellulose fibrils and microfibrils derived from the plant material which comprises:
 producing a first pulp of the plant material;   mixing a first pulp with a bleach solution so that a quantity of pectins and hemicelluloses present within the plant material are dissolved within a resultant solution;   producing a second pulp by removing the bleach from the resultant solution; and   homogenising the second pulp so as to reduce the cellulose in the second pulp to individual cellulose fibrils and microfibrils.   
     
     
         23 . The method of  claim 11 , comprising a method of obtaining a sample of individual cellulose fibrils and microfibrils derived from the plant material which comprises:
 producing a first pulp of the plant material;   mixing a first pulp with a bleach solution so that a quantity of pectins and hemicelluloses present within the plant material are dissolved within a resultant solution;   homogenising the resultant solution so as to reduce the cellulose in the second pulp to individual cellulose fibrils and microfibrils; and   removing the bleach from the homogenised solution.   
     
     
         24 . The method of  claim 22 , wherein the homogenising step is carried out using high shear mixing. 
     
     
         25 . The method of  claim 21 , wherein the homogenising is carried out using high pressure homogenisation up to 1000 bar. 
     
     
         26 . The method of  claim 13 , wherein the ratio of the hydrophobic binder to the water within the second emulsion is between 10:1 and 1:5. 
     
     
         27 . The method of  claim 26 , wherein the ratio of the hydrophobic binder to the water within the second emulsion is between 10:1 and 5:1. 
     
     
         28 . The method of  claim 13 , wherein the step of removing water from the paste material comprises applying a vacuum to the paste. 
     
     
         29 . The method of  claim 27 , wherein the step of removing water further comprises air drying the paste at a temperature below 120° C. 
     
     
         30 . The method of  claim 13 , wherein the curing of the dried paste material comprises a first curing of the dried paste material at a temperature within the range from ambient to 80°-160° C. 
     
     
         31 . The method of  claim 30 , wherein the step of curing of the dried paste material further comprises a second curing of the dried paste material at a temperature within the range 120°-180° C. 
     
     
         32 . The method of  claim 30 , wherein the step of curing of the dried paste material further comprises a second curing of the dried paste material at a temperature within the range 120°-180° C. 
     
     
         33 . The method of  claim 7 , wherein the hydrophilic binder comprises a hydrophilic or substantially hydrophilic polymer selected from the group consisting of hemicellulose, an acrylic resin, a partially hydrolysed polyvinyl acetate and a biological hydrophilic polymer. 
     
     
         34 . The method of  claim 7 , wherein the hydrophobic binder is selected from a member of the group consisting of a hydrophobic polymer, polyurethane, phenolic resin, acrylic, epoxy resin and siloxane. 
     
     
         35 . A method for producing a laminate structure, comprising:
 applying a hydrophobic resin to preformed sheets of biocomposite material, stacking the sheets on top of one another and
 applying pressure. 
   
     
     
         36 . A method for producing a laminate structure comprising two or more layers wherein at least one layer comprises a biocomposite material, said method comprising: preparing the biocomposite material according to the method of  claim 11 . 
     
     
         37 . A method of  claim 36 , wherein the laminate structure forms a tubular structure. 
     
     
         38 . A method of  claim 37 , wherein the laminate structure is a fishing rod, bicycle frame, ski pole, sail spar or a mast.