Method of joining polymeric biomaterials

Abstract

According to an example aspect of the present invention, there is provided a method of joining objects of hydrophilic polymeric biomaterials. In the method, an ionic liquid is applied onto the surfaces of the objects; the surfaces are pressed together; and the ionic liquid is removed. The method produces a product that can consist to 100% of biomaterial, with no synthetic polymer or chemicals remaining in the product.

1 . A method of joining objects to one another, the method comprising:
 applying an ionic liquid onto at least one surface of the objects; and   pressing the surfaces together to join the objects together,   wherein at least one of objects comprises a hydrophilic polymeric biomaterial, and   wherein the ionic liquid comprises a salt of an alkylated acyclic guanidium, a bicyclic amidine, or a bicyclic guanidine with a carboxylic acid.   
     
     
         2 . The method of  claim 1 , wherein the carboxylic acid is selected from the group consisting of methanoic acid, ethanoic acid, and propanoic acid. 
     
     
         3 . The method of  claim 1 , wherein the ionic liquid comprises 1,1,3,3-tetramethylguanidium acetate, 1,5-diazabicyclo[4.3.0]non-5-enium acetate, or 1-methyl-1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinium acetate. 
     
     
         4 . The method of  claim 1 , wherein the ionic liquid comprises a volatile ionic liquid. 
     
     
         5 . The method of  claim 1 , further comprising partially or completely removing the ionic liquid from the objects. 
     
     
         6 . The method of  claim 5 , wherein the ionic liquid is partially or completely removed by evaporation 
     
     
         7 . The method of  claim 6 , wherein the method further comprises:
 heating the objects before the evaporation at a temperature lower than a temperature at which the ionic liquid partially or completely evaporates in a first heating stage;   partially or completely removing the volatile ionic liquid by evaporation at or above the temperature at which the ionic liquid evaporates in a second heating stage; and   pressing the surfaces together to join the objects together.   
     
     
         8 . The method according to  claim 5 , wherein the ionic liquid is partially or completely removed by desolvation and washing with an antisolvent, by ion metathesis, or by decomposing the volatile ionic liquid. 
     
     
         9 . The method according to  claim 1 , further comprising collecting and recycling the ionic liquid in the method. 
     
     
         10 . The method according to  claim 1 , wherein the amount of the ionic liquid added onto the at least one surface is 0.0003 to 10 g/cm 2. 
     
     
         11 . The method according to  claim 1 , wherein the ionic liquid is added as a mixture or solution comprising an additional component selected from the group consisting of:
 a co-solvent or antisolvent;   excess of a conjugate base or acid;   cellulose;   modified cellulose;   polysaccharides;   polyols;   chitin, chitosan, or modified chitin, silk, or wool;   lignin, modified lignin, or a lignin-derived resin;   pulp, wood or other biomass material pre-swelled and/or pretreated with a water/cosolvent/ionic liquid (IL) mixture;   synthetic polymers;   undissolved fibers;   inorganic modifiers and fillers;   additives to impart resistance to diffusion of oxygen, vapor, or hydrophobic materials;   biocides;   reagents to attack and soften lignin, to acylate or alkylate hydroxyls, to plasticize the biomaterial, or to prevent colourisation; and   combinations thereof.   
     
     
         12 . The method according to  claim 1 , wherein the ionic liquid is applied in a form of a solution, and wherein the solution comprises a gel, a microgel, a suspension, or a physical dispersion. 
     
     
         13 . The method according to  claim 1 , wherein the ionic liquid is added in a solid form and is melted to join the objects. 
     
     
         14 . The method according to  claim 1 , wherein two or more objects composed of the same hydrophilic polymeric biomaterial are joined together. 
     
     
         15 . The method of  claim 1 , wherein each of the objects comprises a hydrophilic polymeric biomaterial. 
     
     
         16 . The method according to  claim 1 , wherein the objects joined together comprise at least a first object and a second object with the first object comprising a different material from that of the second object, the different material selected from the group consisting of hydrophilic polymeric biomaterials, synthetic polymers, and textiles. 
     
     
         17 . The method of  claim 1 , wherein the hydrophilic polymeric biomaterial comprises a porous hydrophilic polymeric biomaterial. 
     
     
         18 . The method of  claim 17 , wherein the porous hydrophilic polymeric biomaterial is selected from the group consisting of wood, paper, straw, leather, and combinations thereof. 
     
     
         19 . The method according to  claim 1 , wherein the ionic liquid is added as a mixture or solution comprising the liquid and a co-solvent. 
     
     
         20 . The method according to  claim 19 , wherein the co-solvent comprises acetone.