U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            LIANG, SONGMIAO - RUTGERS UNIV.NEW JERSEYitem
                                            Liu, Linshuitem
                                            HUANG, QINGRONG - RUTGERS UNIV.NEW JERSEYitem
                                            YAN, KIT KEITH - RUTGERS UNIV.NEW JERSEY
  Submitted to: Journal of Physical Chemistry
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 3/10/2009
                                    Publication  Date: 4/15/2009
                                    Citation: Liang, S., Liu, L.S., Huang, Q., Yan, K.L. 2009. Unique rheological behavior of chitosan modified nanoclay at highly hydrated state. Journal of Physical Chemistry B. 113(17):5823-5828.Interpretive Summary: The technology of controlled release of active substances (CRAS) is a hundred billion dollar market, covering various areas from pharmaceuticals and cosmetics, to active packaging and agribusiness. Nanoclay can be converted to delivery vehicles for CRAS by complexation with polysaccharides or synthetic hydrocolloids. The present study evaluated the structure and properties of chitosan/clay nanoparticles to expand their industrial utilization. Furthermore, the study brings us one step closer to developing a series of intelligent packaging/wrapping/coating materials from pectin and other byproducts of agricultural processing. Eventually, the development of these new materials will expand the market for the products and byproducts from agricultural processing.
                                Technical Abstract: Chitosan/exfoliated clay nanocomposites (CCNs) were prepared using our newly developed method which is based on an electrostatic adsorption process and pre-exfoliated silicate clay. Atomic force microscopy, optical microscopy and rheological technology are employed to clarify the effect of the initial chitosan-clay weight ratio (m) on mesostructure and rheological behavior of CCNs. Mechanism analysis on the formation of mesostructure and the unique rheological behavior of CCNs is further performed. Our results indicate that a critical saturated adsorption ratio is observed to exist at m = 0.16. Increase of m gives rise to an interesting evolution in the mesostructure from smooth to porous network, which is attributed to the formation of a clay-connected structure at m < 0.16 and a chitosan-bridged structure at m > 0.16. Dynamic rheological tests indicate that both stress-strain behavior and moduli of CCNs exhibit a strong dependence on the initial ratio m. Shear-thinning behavior is observed and further confirmed by steady-state shear testing. Interestingly, two unique transitions, denoted as a small peak for CCNs with m > 0.06 at 10.0 < sheer rate < 30.0 s-1 and a sharp drop for CCNs with m = 0.16 at 0.2 < sheer rate < 0.5 s-1 in the shear viscosity, appear during the shearing process. Pre-shearing tests show that the mesostructure stability of CCNs has been effectively enhanced by the bridging effect of chitosan at higher m, though possessing an irreversible shearing-induced breakage. In combination with the evolution in the mesostructure, we conclude that the above rheological behaviors are mainly determined by the amount of adsorbed chitosan on clay surface through strong electrostatic interaction along with other interactions.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov