Modulating nanocellulose hydrogels and cryogels strength by crosslinking and blending

编号 020032102

推送时间 20211213

研究领域 林产化工 

年份 2021 

类型 期刊 

语种 英语

标题 Modulating nanocellulose hydrogels and cryogels strength by crosslinking and blending

来源期刊 Colloids and Surfaces A: Physicochemical and Engineering Aspects

期 第321期

发表时间 20210922

关键词 Mechanical strength;  Nanocellulose;  Hydrogel;  Cryogel;  Cellulose nanocrystal; 

摘要 The mechanical strength of hydrogels and cryogels made from carboxylated?nanocellulose?(NC) fibers can be modulated by chemically/physically crosslinking and blending with different fibrils (shorter/longer). Nanocellulose hydrogels are produced by oxidizing Bleached Eucalyptus Kraft (BEK) pulp followed by high pressure mechanical treatment.?Polyethyleneimine?(PEI) and hexamethylenediamine (HMDA) were selected to crosslink nanocellulose hydrogels physically and chemically, respectively. Shorter?cellulose nanocrystals?(CNC) and longer?microcrystalline?cellulose (MCC) fibrils were blended with the TEMPO oxidized nano/micro fibers to produce hydrogels of controlled properties. Nanocellulose cryogels were prepared from these hydrogels by a two steps process of freezing and lyophilization. The?mechanical properties?of nanocellulose hydrogels and cryogels were modulated by controlling the type and density of crosslinking as well as by blending with nano- or microfibrils. Chemical crosslinking (HMDA) increases the hydrogel elastic?compression moduli?(G′) but does not significantly affect the?compressive strength?of the cryogel. SAXS reveals the HMDA crosslinked hydrogel to be structurally homogeneous. Physical crosslinking with high molecular weight PEI increases the?storage modulus?(G′) of nanocellulose hydrogels. Blending a carboxylated nanocellulose fiber suspension with CNC significantly increases the cryogel compressive strength. Nanocellulose gel exhibits tuneable mechanical strength and absorption capacity from the crosslinking/blending strategy (type and density); this improved fundamental knowledge of the fiber-crosslinker and fiber-cellulose crystal interactions enables greater control and tunability of the properties of hydro- and cryogels for personal and infant care products, as agricultural water retention aids, and for?biosensor?applications.

服务人员 尚玮姣

服务院士 宋湛谦

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