A Novel Associative Polymer Network based on Cyclodextrin Inclusion with Tunable Rheological Properties

2006 ◽  
Vol 947 ◽  
Author(s):  
Lin Fu ◽  
Xuhong Guo ◽  
Stephen Lincoln ◽  
Robert K. Prud'homme
Keyword(s):  
Rheological Properties ◽  
Polymer Network ◽  
Sodium Dodecylsulfate ◽  
Titration Calorimetry ◽  
Temperature Sensitive ◽  
Associative Polymers ◽  
Alkyl Chains ◽  
Alkyl Groups ◽  
Dynamic Rheological Properties ◽  
Associative Polymer

ABSTRACTA novel associative polymer network with tunable rheological properties is developed based on cyclodextrin-hydrophobe inclusion. The network is formed from mixtures of two polyacrylic acid (PAA) backbone polymers, one with pendant cyclodextrin groups and one with pendant hydrophobic alkyl groups. The lifetime of the cyclodextrin-hydrophobe inclusion can be well controlled by the length of alkyl chains inserted into the cyclodextrins; also, the binary nature of cyclodextrin-hydrophobe inclusion prevents hydrophobes from forming non-stoichiometric multiple associations. This system can serve as a model associative polymer network to test associative polymers theories. Dynamic rheological properties of this mixture solution can be tuned by adding free cyclodextrins or sodium dodecylsulfate (SDS) to displace polymer to polymer associations. Dynamic moduli change three orders of magnitude from a gel state to a sol state. This polyelectrolyte system is also pH sensitive, salt sensitive and temperature sensitive. The phase behavior of this mixture solution is experimentally studied by light scattering measurements and rheology. The thermodynamics of the cyclodextrin-hydrophobe interaction is independently studied using isothermal titration calorimetry and surface plasmon resonance study.

scholarly journals Crystal structure of thermostable alkylsulfatase SdsAP from Pseudomonas sp. S9

2017 ◽  
Vol 37 (3) ◽  
Author(s):  
Lifang Sun ◽  
Pu Chen ◽  
Yintao Su ◽  
Zhixiong Cai ◽  
Lingwei Ruan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Sodium Dodecyl ◽  
Titration Calorimetry ◽  
Pseudomonas Sp ◽  
Sterol Carrier Protein ◽  
Dimerization Domain ◽  
Alkyl Chains ◽  
Hydrolysis Of

A novel alkylsulfatase from bacterium Pseudomonas sp. S9 (SdsAP) was identified as a thermostable alkylsulfatases (type III), which could hydrolyze the primary alkyl sulfate such as sodium dodecyl sulfate (SDS). Thus, it has a potential application of SDS biodegradation. The crystal structure of SdsAP has been solved to a resolution of 1.76 Å and reveals that SdsAP contains the characteristic metallo-β-lactamase-like fold domain, dimerization domain, and C-terminal sterol carrier protein type 2 (SCP-2)-like fold domain. Kinetic characterization of SdsAP to SDS by isothermal titration calorimetry (ITC) and enzymatic activity assays of constructed mutants demonstrate that Y246 and G263 are important residues for its preference for the hydrolysis of ‘primary alkyl’ chains, confirming that SdsAP is a primary alkylsulfatase.

scholarly journals Rheological properties of hydroxypropylmethyl cellulose/sodium dodecylsulfate mixtures

2014 ◽  
Vol 79 (4) ◽  
pp. 457-468 ◽  
Author(s):  
Jaroslav Katona ◽  
Sandra Njaradi ◽  
Verica Sovilj ◽  
Lidija Petrovic ◽  
Brankica Marceta ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Sodium Dodecylsulfate ◽  
Shear Thinning ◽  
Cellulose Ether ◽  
Flow Profile ◽  
Hydroxypropylmethyl Cellulose ◽  
Shear Rates ◽  
Newtonian Liquids ◽  
Shear Induced Structure ◽  
Induced Structure

Rheological properties of mixtures of hydroxypropylmethyl cellulose (HPMC), a nonionic associative cellulose ether, and sodium dodecylsulfate (SDS), an anionic surfactant, were investigated by viscosity measurements performed at different shear rates (0.1-6000 s-1). HPMC/SDS mixtures containing different concentrations of SDS (CSDS=0.00-3.50 % w/w) and HPMC concentrations which corresponded to the overlap parameter c/c*=3, 6, and 12 were prepared. All HPMC/SDS mixtures were found to be shear-thinning when examined in a low-end-to mid-range of the applied shear rates. The degree of shear-thinning, n, and viscosity of the mixtures were influenced by composition of HPMC/SDS mixtures and HPMC-SDS complex formation. The changes in n ranged from values typical for highly shear thinning to almost perfectly Newtonian liquids, and were more pronounced as c/c* was increased from 3 to 6 and 12. A change in flow profile and a buildup of the first normal stress difference (N1) was observed in HPMC/SDS mixtures with c/c*=6 and 12 and CSDS 0.55-1.00 % and 0.55-2.50 %, respectively, when a critical shear rate, crit. was exceeded, suggesting that a shear-induced structure formation in the mixtures took place.

Dynamic Rheological Properties of Wheat Starch-Gluten Doughs

1999 ◽  
Vol 76 (1) ◽  
pp. 105-109 ◽  
Author(s):  
K. A. Miller ◽  
R. C. Hoseney
Keyword(s):  
Rheological Properties ◽  
Wheat Starch ◽  
Dynamic Rheological Properties

scholarly journals Effect of pre-shearing on the steady and dynamic rheological properties of mud sediments

2020 ◽  
Vol 116 ◽  
pp. 104338 ◽  
Author(s):  
Ahmad Shakeel ◽  
Alex Kirichek ◽  
Claire Chassagne
Keyword(s):  
Rheological Properties ◽  
Dynamic Rheological Properties

Physical Principles Underlying the Complex Biology of Intracellular Phase Transitions

2020 ◽  
Vol 49 (1) ◽  
pp. 107-133 ◽  
Author(s):  
Jeong-Mo Choi ◽  
Alex S. Holehouse ◽  
Rohit V. Pappu
Keyword(s):  
Phase Transitions ◽  
Rheological Properties ◽  
Recent Work ◽  
Driving Forces ◽  
Rna Molecules ◽  
Associative Polymers ◽  
Different Types ◽  
Condensate Formation ◽  
The Impact ◽  
Physical Principles

Many biomolecular condensates appear to form via spontaneous or driven processes that have the hallmarks of intracellular phase transitions. This suggests that a common underlying physical framework might govern the formation of functionally and compositionally unrelated biomolecular condensates. In this review, we summarize recent work that leverages a stickers-and-spacers framework adapted from the field of associative polymers for understanding how multivalent protein and RNA molecules drive phase transitions that give rise to biomolecular condensates. We discuss how the valence of stickers impacts the driving forces for condensate formation and elaborate on how stickers can be distinguished from spacers in different contexts. We touch on the impact of sticker- and spacer-mediated interactions on the rheological properties of condensates and show how the model can be mapped to known drivers of different types of biomolecular condensates.

Effect of stretching speed on morphologies and properties of in situ microfibrillar POE/PLA composites

2020 ◽  
pp. 089270572093917
Author(s):  
Jing Sun ◽  
Anrong Huang ◽  
Shanshan Luo ◽  
Min Shi ◽  
Heng Luo ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Rheological Properties ◽  
Loss Modulus ◽  
Weight Ratio ◽  
Poly Lactic Acid ◽  
Electron Microscopic ◽  
Dynamic Rheological Properties ◽  
Scanning Electron Microscopic ◽  
Ethylene Octene Copolymer

In situ microfibrillar ethylene–octene copolymer (POE)/poly(lactic acid) (PLA) composites (MFCs) with different phase morphologies were prepared by controlling the stretching speed and maintaining the weight ratio of POE/PLA of 80/20. Four different stretching speeds were employed to study the effect of PLA microfibrillar morphology on tensile, crystalline, and rheological properties of MFCs. Scanning electron microscopic images revealed that the morphology of PLA phase was strongly influenced by stretching speed. MFCs with highest aspect ratio and smaller diameter of PLA microfibrils were obtained with a stretching speed of 60 rpm. The PLA microfibrils with high aspect ratio had the best reinforcement effect on MFCs. The dynamic rheological properties indicated that the MFCs achieved higher storage modulus and loss modulus at the stretching speed of 60 rpm.

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