Developing an Environment for Exploring Distributed Operations: A Wargaming Example

Holden, William T.; Smith, Matthew Lee; Conzelman, Clair E; Smith, Paul; Lickteig, Carl W.; Sanders, William R.

doi:10.21236/ada435131

Cited by 4 publications

(4 citation statements)

References 2 publications

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“…This method produces tailored block copolymers of controlled molecular weight and molecular weight distribution (MWD), chain-end functionalization, and architecture, through precise sequencing of two, three, or even more monomers . It has met great commercial success with SIS (polystyrene- b -polyisoprene- b -polystyrene) and SBS (polystyrene- b -polybutadiene- b -polystyrene) triblock copolymers, despite the stringent synthesis conditions required. More recently, anionic polymerization has been extended to other commercially important vinyl monomers, among which acrylates or methacrylates. − Clever solutions overcoming technical obstacles such as very low reacting temperatures for these copolymers are starting to emerge …”

Section: Introductionmentioning

confidence: 99%

Molecular Disorder and Mesoscopic Order in Polydisperse Acrylic Block Copolymers Prepared by Controlled Radical Polymerization

Ruzette¹,

Tencé‐Girault²,

Leibler³

et al. 2006

Macromolecules

122

151

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Self-assembly of high molecular weight polydisperse acrylic block copolymers and their blends is presented under conditions as close as possible to thermodynamic equilibrium. Di- and triblock copolymers comprising a poly(butyl acrylate) (PBA) first or middle block, and poly(methyl methacrylate) (PMMA) second or outer blocks, denoted MBA and MBAM, respectively, are prepared by nitroxide-mediated polymerization (NMP). Their particularity is that the acrylic block is controlled while the methacrylate block is polymerized via an uncontrolled radical process under the synthesis conditions used. Overall composition and molecular weight polydispersities are large. Molecular disorder does not yield macrophase separation, and TEM on solvent cast films reveals lamellar and poorly ordered bicontinuous, cylindrical, or spherical morphologies. Except for the lamellar phase, clear multiple orders of diffraction are not visible in SAXS, and scattering profiles instead indicate a liquidlike order of microdomains. More importantly, morphology boundaries are strongly shifted compared to those commonly accepted for model monodisperse block copolymers. Hence, symmetric copolymers adopt morphologies with highly curved interfaces while lamellae are displaced to PMMA-rich compositions. These results suggest that unbalanced polydispersity between the two blocks can induce interfacial curvature toward to broadest molecular weight distribution, thereby releasing stretching energy of the whole chain. This effect is expected to be encountered in radical or hybrid block copolymer syntheses whenever control cannot be optimized for all blocks.

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Section: Introductionmentioning

confidence: 99%

Molecular Disorder and Mesoscopic Order in Polydisperse Acrylic Block Copolymers Prepared by Controlled Radical Polymerization

Ruzette¹,

Tencé‐Girault²,

Leibler³

et al. 2006

Macromolecules

122

151

View full text Add to dashboard Cite

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“…Results from four Future Combat System -Command and Control (FCS C2) experiments conducted by the Defense Advanced Research Projects Agency (DARPA) revealed that the co-located command group engaged in a fast-paced and flexible verbal exclange during simulated engagements (Lickteig, Sanders, Durlach, Lussier, & Carnahan, )03). In sharp contrast, during experimentation with distributed command group members it was noted that communication was less frequent, and more closely resembled sequential staff briefings (Holden, et al, 2005). A similar relationship was noted in preliminary experimentation supporting the development of the REPSS.…”

Section: Introductionmentioning

confidence: 77%

Collaborative Planning in Network-Enabled Co-Located and Distributed Environments

Sanders¹,

Fultz²

2008

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“…A common approach is the combination of rather brittle and stiff polymers exhibiting high glass temperature (high- T g ), e.g., polystyrene (PS), with a soft and rubbery polymer with low glass temperature (low- T g ), e.g., polybutadiene or polyisoprene (PI) . By this combination, and depending on the comonomer ratio employed, either elastically as well as plastically deformable, tough thermoplastic elastomers or high impact materials with an operating window from roughly −65 °C ( T g (PI)) up to 100 °C ( T g (PS)) are obtained. However, a simple AB diblock architecture cannot impart the desired mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Linear (IS)_nI Multiblock Copolymers: Tailoring the Softness of Thermoplastic Elastomers by Flexible Polyisoprene End Blocks

et al. 2023

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Nano-segregated morphologies and the resulting thermoplastic elastomer (TPE) properties, e.g., in multiblock copolymers based on isoprene (I) and styrene (S), depend on chain architecture (overall molar mass, block number, composition profile). In this work nonconventional (IS) n I type multiblock copolymers possessing two flexible polyisoprene end blocks are introduced. Molar masses between 120 and 400 kg·mol–1 and block numbers ranging from 3 to 13 with either precisely defined blocks or tapered segment structures were obtained by (i) sequential monomer addition or (ii) statistical S/I copolymerization steps, respectively. All polymers are based on a 30/70 molar ratio styrene/isoprene (36 vol % PS). The materials were investigated with respect to their self-assembly and mechanical response, respectively, by small-angle X-ray scattering (SAXS) and tensile tests. While the sequential multiblock copolymers generally exhibited strong segregation into well-ordered lamellar morphologies and more extended chain conformations, their tapered counterparts showed only weak order and a smaller scaling exponent δ with d ∼ N δ. In addition, a higher bridge-to-loop ratio was found for the sequential multiblock copolymers. On the other hand, the tapered structures exhibited accessible order–disorder transition temperatures for low molar masses and high block numbers, which is relevant for processing. Generally, tensile tests revealed high toughness (20–70 MJ·m–3) for the multiblock copolymers bearing at least two polystyrene blocks, with the tapered structures being softer and more flexible. The stiffness also increased with increasing block number, reflecting shrinking of the domain sizes. Moreover, the maximum deformation was found to increase with the overall molar mass. With their soft, albeit resilient properties, these materials with low T g polyisoprene end blocks are promising as a substitute for plasticized polymers, e.g., poly(vinyl chloride), avoiding migration and release of a plasticizer.

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Developing an Environment for Exploring Distributed Operations: A Wargaming Example

Cited by 4 publications

References 2 publications

Molecular Disorder and Mesoscopic Order in Polydisperse Acrylic Block Copolymers Prepared by Controlled Radical Polymerization

Molecular Disorder and Mesoscopic Order in Polydisperse Acrylic Block Copolymers Prepared by Controlled Radical Polymerization

Collaborative Planning in Network-Enabled Co-Located and Distributed Environments

Linear (IS)_nI Multiblock Copolymers: Tailoring the Softness of Thermoplastic Elastomers by Flexible Polyisoprene End Blocks

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Developing an Environment for Exploring Distributed Operations: A Wargaming Example

Cited by 4 publications

References 2 publications

Molecular Disorder and Mesoscopic Order in Polydisperse Acrylic Block Copolymers Prepared by Controlled Radical Polymerization

Molecular Disorder and Mesoscopic Order in Polydisperse Acrylic Block Copolymers Prepared by Controlled Radical Polymerization

Collaborative Planning in Network-Enabled Co-Located and Distributed Environments

Linear (IS)nI Multiblock Copolymers: Tailoring the Softness of Thermoplastic Elastomers by Flexible Polyisoprene End Blocks

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Product

Resources

About

Linear (IS)_nI Multiblock Copolymers: Tailoring the Softness of Thermoplastic Elastomers by Flexible Polyisoprene End Blocks