Structure—Property Relationships in Polymers

Seymour, Raymond B.; Carraher, Charles E.

doi:10.1007/978-1-4684-4748-4

Cited by 102 publications

(72 citation statements)

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“…Crystalline polymers melt at their melting point T m . 6 Starch components, amylose and amylopectin, are organized in structures consisting of crystalline, partially crystalline, and amorphous areas. In native granular starches, amylopectin exhibits partial crystallinity, and amylose is believed to exist in the amorphous noncrystalline state.…”

mentioning

confidence: 99%

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Blanche

Sun

2004

Adv Polym Technol

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ABSTRACT:The objective of this study was to investigate the relationships between starch melt transition characteristics, extrusion conditions, and final product properties. Cornstarch was extruded using a corotating twin-screw extruder at varying moisture content, medium/high screw configuration, and 300/400-rpm screw speeds. Extrudates were evaluated for bulk density, expansion ratio, cell structure, bending strength, thermal and pasting properties. Temperature change ( T) was defined as the temperature difference between the native starch melting temperature and its melt temperature just behind the die during extrusion at a given moisture content. T was significantly affected by starch moisture content and mechanical shearing, which controlled the melting behavior of the starch in the barrel. Amylose-lipid complex formation during extrusion increased as T increased and leveled off at T of about 20• C. Pasting peak viscosity of the starch extrudates decreased as T increased and leveled off at T of about 15• C. Within the same range of mechanical shearing intensity, extrudate bulk density and bending strength decreased linearly as T increased. Extrudate expansion was negatively correlated to bulk density. C

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confidence: 99%

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Blanche

Sun

2004

Adv Polym Technol

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“…The effect of compacting pressure on physico-mechanical properties such as density, tensile strength (TS), and elongation are presented in Table 2. It was observed that as the pressure increased, the TS increases and reaches an optimum value of 22.2 MPa at a pressure of 6.9 MPa, beyond which the TS decreased, which was attributed to the reduction in the free volume and increased association between PVAc and fibres of NC and cellulose, and subsequent bonding increased, resulting into increase in TS 17 . In the second set of experiments, compacting pressure was fixed at 6.9 MPa, while the temperature of mould was varied over the range 60115 °C with an increment of 10 °C.…”

Section: Resultsmentioning

confidence: 99%

“…Closed vessel 17 , Hounsfield tensometer, DTA, vacuum stability apparatus and methyl violet test apparatus were used for ballistic evaluation, improvement of mechanical properties, determination of decomposition Table 1. Analysis results of raw materials as ingredients of the formulations temperature, vacuum and thermal stability of the CCC, respectively.…”

Section: Equipmentmentioning

confidence: 99%

Polyvinyl Acetate Resin as a Binder Effecting Mechanical and CombustionProperties of Combustible Cartridge Case Formulations

Shedge

Patel

Tadkod

et al. 2008

DSJ

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Several combustible cartridge case (CCC) formulations containing nitrocellulose (NC) as an energetic ingredient with diphenylamine (DPA) as stabiliser, cellulose fiber as reinforcing material and polyvinyl acetate (PVAc) as a binder are processed to form combustible discs. A formulation containing nitrocellulose (83 parts), cellulose (17 parts) , PVAc (20 parts) and diphenylamine (1 part) by weight was observed with the improvement of mechanical properties without any adverse effect on combustion characteristics, safety parameters and compatibility with triple base multi-tubular propellant. Dynamic firing performance was also satisfactory.

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“…The introduction of the polar bromine groups into the network by the Di-BrSAGMA comonomers should have an increasing effect on the T g as compared to the OAGMA polymers, due to polar interactions between the fatty acid chains. 11 On the other hand, bromine increases the bulkiness of the pendant fatty acid chain and also decreases the crosslink density of the network. It appears that these factors offset, thereby similar resin formulations of OAGMA and Di-BrSAGMA have similar T g .…”

Section: Polymer Propertiesmentioning

confidence: 99%

The synthesis of 9–10 Dibromo stearic acid glycidyl methacrylate and its use in vinyl ester resins

Can

Scala

Sands

et al. 2007

J of Applied Polymer Sci

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In this study, 9-10 dibromo stearic acid glycidyl methacrylate (Di-BrSAGMA) was synthesized from oleic acid and used as a replacement for styrene in vinyl ester (bisphenol A type VE (VE 828) and Novalac type VE (VE160)) to introduce fire retardance to these systems and to decrease the volatile organic compound (VOC) emissions caused by styrene. When the Di-BrSAGMA was used as the comonomer, these resins exhibited too high viscosities, reduced modulus and glass transition temperature (T g ) values compared to those of the styrene based systems. Thus, the Di-BrSAGMA was used in the presence of styrene in these resins. The viscosities of the resins with various Di-BrSAGMA contents were determined and the modulus and the T g values of the resulting polymers were measured via dynamic mechanical analysis (DMA) to determine the ideal formulations for each resin system. Similar analysis was performed, with similar oleic acid glycidyl methacrylate (OAGMA) contents, to determine the effect of the introduction of the bromine groups onto the network. Reactive diluent blends of the fatty acid based monomers with styrene, at styrene contents as low as 15-20 wt % at 35-45 wt % total comonomer content, in VE formulations were shown to have processable viscosities for liquid molding processes, and modulus and T g values that are comparable to those of the commercial VE-styrene systems. The effect of the replacement of styrene by the Di-BrSAGMA monomer on the thermal degradation behavior of the VE 828 and VE 160 networks was also explored by thermal gravimetric analysis (TGA).

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Structure—Property Relationships in Polymers

Cited by 102 publications

References 0 publications

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

Polyvinyl Acetate Resin as a Binder Effecting Mechanical and CombustionProperties of Combustible Cartridge Case Formulations

The synthesis of 9–10 Dibromo stearic acid glycidyl methacrylate and its use in vinyl ester resins

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