Nanocellulose nucleating agents for crystallization of polylactides and other polymers

Abstract

The invention provides a polymer composition comprising from 50 wt % to 99.9 wt % polymer, from 0.1 wt % to 10 wt % nanocellulose as a first nucleating agent, and from 0.01 wt % to 5 wt % of a second nucleating agent. In some embodiments, the polymer is polylactide, the first nucleating agent is lignin-containing nanocellulose, and the second nucleating agent is a sulfur-containing, oxygenated aromatic molecule. The oxygenated aromatic molecule may be an aromatic sulfonic acid or salt, such as dimethyl 5-sulfoisophthalate. In other embodiments, the sulfur-containing, oxygenated aromatic molecule is lignosulfonic acid. Other variations provide a polymer composition comprising polymer, lignin-containing nanocellulose as a dispersing agent, and additives selected from nucleating agents, compatibilizers, plasticizers, fillers, antioxidants, colorants, or flame retardants. Other variations provide a polymer nucleating agent comprising lignin-containing nanocellulose and a sulfur-containing, oxygenated aromatic molecule. This may be a nucleating agent for polylactide, polycaprolactone, polyhydroxybutyrate, polyethylene, or polypropylene, for example.

What is claimed is: 
     
         1 . A polylactide composition comprising from about 50 wt % to about 99.9 wt % polylactide, from about 0.1 wt % to about 10 wt % nanocellulose as a first nucleating agent, and from about 0.01 wt % to about 2 wt % of a sulfur-containing, oxygenated aromatic molecule as a second nucleating agent. 
     
     
         2 . The polylactide composition of  claim 1 , wherein said first nucleating agent is present from about 0.2 wt % to about 5 wt %. 
     
     
         3 . The polylactide composition of  claim 1 , wherein said second nucleating agent is present from about 0.02 wt % to about 1 wt %. 
     
     
         4 . The polylactide composition of  claim 1 , wherein the total concentration of said first nucleating agent and said second nucleating agent is from about 0.2 wt % to about 5 wt %. 
     
     
         5 . The polylactide composition of  claim 4 , wherein the total concentration of said first nucleating agent and said second nucleating agent is from about 0.3 wt % to about 2 wt %. 
     
     
         6 . The polylactide composition of  claim 1 , wherein the ratio of said first nucleating agent to said second nucleating agent is from about 10 to about 1. 
     
     
         7 . The polylactide composition of  claim 6 , wherein the ratio of said first nucleating agent to said second nucleating agent is about 8. 
     
     
         8 . The polylactide composition of  claim 1 , wherein said sulfur-containing, oxygenated aromatic molecule is an aromatic sulfonic acid or salt thereof. 
     
     
         9 . The polylactide composition of  claim 8 , wherein said aromatic sulfonic acid or salt thereof is dimethyl 5-sulfoisophthalate in acid or salt form. 
     
     
         10 . The polylactide composition of  claim 1 , wherein said sulfur-containing, oxygenated aromatic molecule is lignosulfonic acid or a salt thereof. 
     
     
         11 . The polylactide composition of  claim 1 , wherein said nanocellulose is hydrophobic nanocellulose. 
     
     
         12 . The polylactide composition of  claim 11 , wherein said hydrophobic nanocellulose is lignin-containing nanocellulose. 
     
     
         13 . The polylactide composition of  claim 11 , wherein said hydrophobic nanocellulose is lignin-coated nanocellulose. 
     
     
         14 . The polylactide composition of  claim 1 , wherein said nanocellulose includes sulfonated lignin that is chemically and/or physically bonded to said nanocellulose. 
     
     
         15 . The polylactide composition of  claim 1 , wherein said polylactide composition includes a second polymer that is co-polymerized with said polylactide. 
     
     
         16 . The polylactide composition of  claim 1 , wherein said composition further comprises one or more additives selected from the group consisting of compatibilizers, plasticizers, fillers, antioxidants, colorants, flame retardants, and combinations thereof. 
     
     
         17 . The polylactide composition of  claim 1 , wherein said composition further comprises one or more additives selected from the group consisting of glass fibers, mica, talc, metal powder, silica, calcium carbonate, carbon, wollastonite, stearates, and combinations thereof. 
     
     
         18 . The polylactide composition of  claim 1 , wherein said composition is in the form of a blend, masterbatch, pellet, extrusion feed, molding feed, extruded part, injection-molded part, blow-molded part, spun fiber, layered sheet, film, foam, container, bag, engineered part, 3D-printing substrate, 3D-printed part, or a combination thereof. 
     
     
         19 . A polymer composition comprising from about 50 wt % to about 99.9 wt % polymer, from about 0.1 wt % to about 10 wt % lignin-containing nanocellulose as a dispersing agent, and from about 0.01 wt % to about 20 wt % of one or more additives selected from the group consisting of nucleating agents, compatibilizers, plasticizers, fillers, antioxidants, colorants, flame retardants, and combinations thereof. 
     
     
         20 . A polymer nucleating agent comprising from about 50 wt % to about 99 wt % lignin-containing nanocellulose and from about 1 wt % to about 50 wt % of a sulfur-containing, oxygenated aromatic molecule.