Laser Light Scattering Study on Aggregation of Cellulose Diacetate in Acetone

We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.

Novel antibacterial cellulose diacetate-based composite 3D scaffold as potential wound dressing

In this work,novel antibacterial cellulose diacetate/poly(ethylenimine)/hyaluronic acid(CDA/PEI/HA)composite three-dimension(3D)scaffolds were prepared through electrospinning and post-processing.Firstly,CDA/PEI 2D composite nanofiber membranes were prepared by electrospinning,and then the CDA/PEI/HA 3D composite scaffolds were fabricated by post-processing and freeze-drying of CDA/PEI membranes.In particular,HA was added to improve the biocompatibility of composite scaffolds.Compared with CDA/PEI scaffolds,CDA/PEI/HA composite scaffolds showed higher water absorbing rate,higher water retention rate and higher mechanical strength.Moreover,CDA/PEI/HA composite scaffolds with abundant positive charge were benefit for improving antibacterial activity.CDA/PEI/HA scaffolds with biology function of HA were benefit for improving hemocompatibility and cell proliferation of CDA/PEI scaffolds.In summary,antibacterial CDA/PEI/HA scaffolds could protect wound from bacterial infection,improve cellular behavior and accelerate wound healing.Thus,CDA/PEI/HA scaffolds could be potential application for wound dressing.

Preparation of green cellulose diacetate-based antibacterial wound dressings for wound healing

Managing wounds is a growing universal problem and developing effective wound dressings to staunch bleeding and protect wounds from bacterial infections is an increasingly serious challenge.In this work,a remolding electrospinning nanofiber three-dimensional structure wound dressing(CCP)was prepared with superhydrophilicity,high water absorption and absorbing capacity,excellent hemostatic capacity and antibacterial ability,and biocompatibility to promote wound healing.Polyhexamethylene guanidine hydrochloride(PHMG)was grafted to cellulose diacetate(CDA)wound dressing surface through an amide reaction.A water contact angle analysis demonstrated that CCP wound dressing could be beneficial to promote wound exudate management effectively with rapid absorption of water within 0.2 s.In vitro hemo-and cytocompatibility assay showed that a CCP wound dressing had no significant hemotoxicity or cytoxicity.Specifically,CCP wound dressings could be beneficial to accelerate wound hemostasis and further reduce mortality caused by uncontrolled bleeding.Furthermore,CCP wound dressings have an excellent antibacterial ability,which could be beneficial to inhibit wound inflammatory over-reaction and promote normal wound healing.Combined together,the prepared wound dressing in this research effort is expected to have high-potential in clinical applications.

Cellulose Acetate Thermoplastics with High Modulus, Dimensicnal Stability and Anti-migration Properties by Using CA-g-PLA as Macromolecular Plasticizer

Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.