Melt spinning of thermotropic cellulose derivatives

Gilbert, R. D.; Venditti, Richard A.; Chun-shan, Zhang; Koelling, Kurt W.

doi:10.1002/(sici)1097-4628(20000711)77:2<418::aid-app19>3.0.co;2-i

Cited by 16 publications

(5 citation statements)

References 9 publications

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“…An alternative interpretation to the lack of Newtonian behavior and to the complex structural organization at large shear rates may be offered based on the two fluids hypothesis [15][16]. The development of two layers of oriented fluids flowing at different rates in the slit was proposed to explain the negative extrudate-swell observed in liquid crystalline polymers [16] and the skin-core morphology of the corresponding extrudates [1,20,[22][23][24][25][29][30]. Following this scenario, POM images should be characteristic of the fluid layer developing close to the slit wall, whereas the SALS patterns mostly probe the structure of the central fluid.…”

Section: Resultsmentioning

confidence: 71%

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Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

Teixeira

Fernandes

Canejo

et al. 2015

Polymer

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The rheological and structural characteristics of acetoxypropylcellulose (APC) nematic melt are studied at shear rates ranging from 10 s -1 to 1000 s -1 which are relevant to extrusion based processes. APC shows a monotonic shear thinning behavior over the range of shear rates tested. The negative extrudate-swell shows a minimum when a critical shear rate ߛሶ is reached. For shear rates smaller than ߛሶ , the flow-induced texture consists in two set of bands aligned parallel and normal to the flow direction. At shear rates larger than ߛሶ , the flow induced texture is reminiscent from a 2 fluids structure. Close to the shearing walls, domains elongated along the flow direction and stacked along the vorticity are imaged with POM, whereas SALS patterns indicate that the bulk of the sheared APC is made of elliptical domains oriented along the vorticity. No full nematic alignment is achieved at the largest shear rate tested. Below ߛሶ , the stress relaxation is described by a stretched exponential. Above ߛሶ , the stress relaxation is described by a fast and a slow process. The latter coincides with the growth of normal bands thicknesses, as the APC texture after flow cessation consists in two types of bands with parallel and normal orientations relative to the flow direction. Both bands thicknesses do not depend on the applied shear rate, in contrast to their orientation.

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Section: Resultsmentioning

confidence: 71%

“…These textures show similarities with those of liquid crystalline fibers spun from cellulose derivatives [29,30]. No bands aligned along the direction of extrusion could be imaged with the magnification used and within the shear rate range studied.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

Teixeira

Fernandes

Canejo

et al. 2015

Polymer

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“…The second compound commonly used in the formulation step was a curing agent to improve the characteristics of coatings during the step of film formation. [2][3][4][5][6] The curing agent used in this work, HMMM, promoted crosslinking between neighboring particles during the film formation. This helped to improve the mechanical resistance of the film, and the polar functional group in the HMMM aided in promoting a number of interactions with different substrates.…”

Section: Industrial Formulation and Barrier Property Evaluationmentioning

confidence: 99%

“…Certain semicrystalline polymers such as polyvinylidene chloride (PVDC) and polyvinyl chloride (PVC) do present good barrier properties to both water and oxygen, while others such as polyvinyl alcohol (PVOH) provide a good barrier to oxygen in the absence of humidity. [1][2][3][4][5] However it is not desirable to use chlorinated monomers in food packaging, and PVOH fails when water is present.…”

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confidence: 99%

Core–Shell Polymer Adhesive for Aluminized Coatings: From Improved Barrier Properties to Commercial Formulation

Lara

Ouzineb²,

McKenna

2019

Macro Materials & Eng

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The development and formulation of core–shell latex‐based adhesives to improve the adhesion of aluminium to poly(ethylene terephthalate) (PET) films and enhance the permeability of the final laminate to oxygen and water is described. All particles have a soft acrylic component (the shell in core–shell particles) to improve adhesion, and occasionally a hydrophobic core to enhance the permeability. The performance of the different latexes is compared to that of a commercially available reference material. The coatings formed by core–shell nanoparticles present a lower permeability to water than the particles synthesized in the absence of the seed, while the permeability to oxygen is found to be mainly related to the correct deposition of the metallic layer. In terms of the industrial formulation, it is found that a limited amount of a wetting agent (WA) is needed to ensure the correct spreading of the latex onto the PET substrate because of the low levels of surfactant used for the latex production. This compound has a positive effect on the adhesive strength of the coating. A curing agent also improves barrier properties, but the optimal level of this compound is dependent on the degree of crosslinker used in the base latex.

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“…[6][7][8] Melt spinning is a simple process, which offers many advantages compared with solvent or wetfiber spinning, such as no solvents are needed, there are no toxic byproducts, and the production speed is high. [9][10][11] In melt spinning process, the used polymer has to be thermoplastic, [6] therefore pure cellulose is not directly processable by melt spinning. Thermoplastic behavior of cellulose can be improved, for example, by using esterification.…”

Section: Introductionmentioning

confidence: 99%

Melt spinnability of long chain cellulose esters

Willberg‐Keyriläinen

Rokkonen

Malm

et al. 2020

J of Applied Polymer Sci

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Technical and hygienic nonwovens, originating typically from fossil‐based synthetic polymers, are the fastest growing applications in the textile industry. Recently developed thermoplastic cellulose fatty acid esters have polyolefin like rheology properties and therefore the suitability of these cellulose esters for fiber production was evaluated. In this study, the melt spinning of textile fibers has been demonstrated using thermoplastic cellulose octanoate. The mechanical properties of melt spun fibers were analyzed by using tensile testing and both the surface and cross‐section morphology of melt spun fibers were studied using the scanning electron microscopy. The surfaces of the fibers were very smooth and also the cross‐section was very uniform and no porosity was observed. While mechanical properties of the produced fibers are not yet as good as those reported for commercial polypropylene (PP) monofilament fibers, they are somewhat more comparable to other cellulose ester‐based fibers. The melt spinning results indicate that the novel cellulose‐based fibers can provide a renewable and recyclable alternative, for example, spun‐laid PP in several hygienic textile and fully oriented in technical applications in future.

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Melt spinning of thermotropic cellulose derivatives

Cited by 16 publications

References 9 publications

Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

Core–Shell Polymer Adhesive for Aluminized Coatings: From Improved Barrier Properties to Commercial Formulation

Melt spinnability of long chain cellulose esters

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