Na Li

Bio: Na Li is an academic researcher from Chinese Ministry of Education. The author has contributed to research in topics: Hygroscopy & Carboxymethyl cellulose. The author has an hindex of 5, co-authored 6 publications receiving 550 citations.

Preparation method of nanometer resin with high hygroscopy

Abstract: The invention discloses a preparation method of nanometer resin with high hygroscopy, which comprises the following steps: adopting crylic acid monomers to carry out graft copolymerization on carboxymethylcellulose; adding organic quaternary ammonium salt to modify montmorillonoid; and preparing CMC/acrylic polymers/OMMT nanometer resin with high hygroscopy through an in situ intercalation polymerization method of aqueous solution. The adoption of the carboxymethylcellulose and the montmorillonoid reduces the dosage of the acrylic polymers, so that the cost is lowered; and after the nanometer resin with the high hygroscopy is dried, the absorption of pure water can be 500g/g, the absorption of normal saline can be 130g/g, the gelstrength can be 13 times of that of the graft copolymerization materials, so the resin has good biodegradation property and can be bio-degraded within 3-4 months and is a green and environment-friendly water retention product. In addition, the raw materials used in the invention, namely the carboxymethylcellulose and montmorillonoid have wide sources, excellent biocompatibility, can remit the shortage of oil resources, and has obvious cost advantages and wide application prospect.

Method for preparing super absorbent resin by using wheat straw

Abstract: The invention relates to a method for preparing super absorbent resin by using wheat straw. As a functional polymer material with super absorption, the super absorbent resin plays an extraordinary role in national economy development and the lives of people. Traditional polymer super absorbent resin is restrained in the process of using due to defaults of high raw material coast, poor salt tolerance, difficult degradation and environment pollution. The present invention provides a process for combining biodegradable super absorbent resin with good salt tolerance by taking wheat straw, acrylicmonomer and MMT as raw materials, and adopting method of grafting modification. The super absorbent resin achieves saline absorption of 140g/g, water retention rate of 53.35 percent, increased intensity which is 140 percent of that of the polymer matrix, and excellent thermal endurance increased by 21 DEG C in comparison with the polymer matrix, has good biological compatibility and degradation, can be degraded in soil and air in 6 to 7 months, and can be widely used in water retention and water conservation of agriculture and forestry.

Preparation method for toughening type leather tanning agent

Abstract: The invention relates to a preparation method for a leather tanning agent, in particular to a preparation method for a leather tanning agent with function of strengthening and toughening collagenous fibers The leather tanning process is a qualitative change process converting raw hide into leather, and can endow the leather with good heat and humidity resistant stability, flexibility and physical and mechanical properties; however, a chrome tanning agent commonly adopted has serious harm to the environment, while a conventional non-chrome tanning agent is hard to meet the requirement on good service performance of the leather The preparation method takes montmorillonite and acrylic monomers as raw materials, and adopts a monomer in-situ intercalation polymerization method to synthesize the toughening type leather tanning agent; and the toughening type leather tanning agent is used for tanning the leather, can greatly improve the strength and toughness of crust leather, and can reduce the dosage of the chrome tanning agent by 75 percent

Polymer Gel Systems for Water Management in High-Temperature Petroleum Reservoirs: A Chemical Review

Abstract: Polymer gel systems as water management materials have been widely used in recent years for enhanced oil recovery applications. However, most polymer gel systems are limited in their ability to withstand the harsh environments of high temperature and high salinity. Those polymer gel systems that can handle high-temperature excessive water treatments are reviewed in this paper and categorized into three major types: in situ cross-linked polymer gels, preformed gels, and foamed gels. Future directions for the development of polymer gel systems for high-temperature conditions are recommended. For excessive water management with temperatures from 80 to 120 °C, current polymer systems are substantially adequate. Polymer gel systems composed of partially hydrolyzed polyacrylamide (HPAM)/chromium can be combined with nanoparticle technology to elongate their gelation time and reduce the adsorption of chromium ions in the formation. Phenolic resin cross-linker systems have reasonable gelation times and gel streng...

Applications of nanocomposite hydrogels for biomedical engineering and environmental protection

Abstract: Nanocomposite hydrogels are polymeric networks that possess a unique property of hydration. The presence of alcohols, carboxylic acids and amides as hydrophilic moieties in structure of nanocomposite hydrogels enhances their stiffness and water-absorbing capacity. Addition of cross-linker in the synthesis of hydrogels increases their stability under extreme conditions of temperature, pH and pressure. Natural polymer-based nanocomposite hydrogels are biodegradable, highly hydrophilic and possess good mechanical strength. Gelatin, chitin, cellulose, pectin, carrageenan, starch and alginate are natural polymers commonly used to fabricate nanocomposite hydrogels. Nanocomposite hydrogels have special characteristics such as high swelling rate, selectivity and stimuli-sensitive nature. Here we review nanocomposite hydrogels for environmental protection and biomedical engineering. Applications in biomedical engineering include drug delivery agents, wound dressing, tissue engineering and antibacterials. Applications in environmental protection include ion exchangers, adsorption, photocatalysis and soil conditioning. Many nanocomposite hydrogels show excellent adsorption selectivity for heavy metal ions: Cu2+ up to 30.35 mg/g, Pb2+ up to 35.94 mg/g, and Zn2+ and Fe3+ up to 94.34 mg/g. Xanthan gum-based nanocomposite hydrogel has removed 96% dye from industrial effluent as reported. In addition, most of the nanocomposite hydrogels showed better adsorption capacity for pollutants in the pH range from 5 to 7. The nanocomposite hydrogels could also be regenerated and successfully utilized for several times. Nanocomposite hydrogels are therefore good bio-absorbent materials for environmental detoxification.