Effect of Hydrolysis on the Strength of Hydrogen Bonds and Tg of Poly(vinylphenol-co-acetoxystyrene)

Kuo, Shiao‐Wei; Liu, Wen-Pin; Chang, Feng‐Chih

doi:10.1021/ma0341824

Cited by 19 publications

(20 citation statements)

References 48 publications

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“…A linear increase of T g was observed with an increase of the mole fraction of adenine and thymine with positive deviation from the Fox equation. Such deviation was attributed to the incorporation of strong hydrogen-bond units. − The more significant T g deviation for adenine-containing polymers compared to thymine-containing polymers suggested stronger self-association of adenine units relative to thymine units at similar molar concentrations.…”

Section: Resultsmentioning

confidence: 99%

Nucleobase Self-Assembly in Supramolecular Adhesives

et al. 2012

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Novel acrylic monomers functionalized with nucleobase-containing units (adenine and thymine) were prepared upon aza-Michael addition and successfully copolymerized with nbutyl acrylate. At a content of 7 mol %, adenine-containing units self-assembled into needle-like microstructures within amorphous polymer matrices as shown with atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), and wide-angle X-ray diffraction (WAXD); thymine-containing units did not aggregate into distinct morphologies even to 30 mol %. Upon blending, thymine-and adenine-containing statistical copolymers associated into a thermodynamically stable complex, which was physically cross-linked through adenine−thymine base pairing. The molar fractions of the nucleobase monomer, nucleobase stacking interactions, and complementary hydrogen bonding principally influenced self-assembly. Additionally, the nucleobasefunctionalized polyacrylates exhibited tunable adhesive and cohesive strength.

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Section: Resultsmentioning

confidence: 99%

Nucleobase Self-Assembly in Supramolecular Adhesives

et al. 2012

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“…The T g value of the block copolymer without His-tag (BA) and with His-tag (HAB 3 , HBA, HBA 2 , and HBA 3 ) were fitted separately by Kwei’s equation (11) and are shown in Figure 9 by dashed line and dash-dot line, respectively. For simplicity, we adopt k = 1 in both cases 70, 71, 73 . For non-His polymer, q = −27.…”

Section: Resultsmentioning

confidence: 99%

“…For simplicity, we adopt k = 1 in both cases. 70,71,73 For non-His polymer, q = À27. For polymers with His-tag, because the His-tag and B have a similar secondary structure, we treated them as one block, which leads to q = 90.…”

Section: Interaction Of Blocks In Spider Silk Block Copolymermentioning

confidence: 99%

Heat Capacity of Spider Silk-Like Block Copolymers

Huang

Krishnaji

et al. 2011

Macromolecules

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We synthesized and characterized a new family of di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, having the form HABn and HBAn (n=1–3), comprising an alanine-rich hydrophobic block, A, a glycine-rich hydrophilic block, B, and a histidine tag, H. The reversing heat capacities, Cp(T), for temperatures below and above the glass transition, Tg, were measured by temperature modulated differential scanning calorimetry. For the solid state, we then calculated the heat capacities of our novel block copolymers based on the vibrational motions of the constituent poly(amino acid)s, whose heat capacities are known or can be estimated from the ATHAS Data Bank. For the liquid state, the heat capacity was estimated by using the rotational and translational motions in the polymer chain. Excellent agreement was found between the measured and calculated values of the heat capacity, showing that this method can serve as a standard by which to assess the Cp for other biologically inspired block copolymers. The fraction of beta sheet crystallinity of spider silk block copolymers was also determined by using the predicted Cp, and was verified by wide angle X-ray diffraction and Fourier transform infrared spectroscopy. The glass transition temperatures of spider silk block copolymer were fitted by Kwei’s equation and the results indicate that attractive interaction exists between the A-block and B-block.

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“…However, for the 95% RH and the intermediate (60 and 45%) RH storage conditions, the experimental Tg mix values appear to plateau at 220 and 190 K, respectively. Under these conditions, enthalpically favored heterointeractions (PLGA/water) may dominate homointeractions (PLGA–PLGA or water–water) to decrease the free volume in the matrix, resulting in an increased Tg mix 35, 36. This type of interaction is more likely at later storage time and higher water content, when carboxylic acid and alcohol PLGA degradation products would experience greater hydrogen‐bonding with water than the initial hydrophobic polymer.…”

Section: Discussionmentioning

confidence: 99%

Physical properties of PLGA films during polymer degradation

Houchin¹,

Topp

2009

J of Applied Polymer Sci

107

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ABSTRACT:The rates of change of polymer properties (glass transition temperature, weight fraction sorbed water, and polymer molecular weight) were determined in poly (DL-lactide-co-glycolide) films under accelerated storage conditions. Films were stored at 70 C and 95%, 75%, 60%, 45%, or 28% relative humidity. Weight fraction sorbed water was determined by thermogravimetric analysis, the glass transition temperature (Tg mix ) of the polymer/water mixture by modulated temperature differential scanning calorimetry, and PLGA number-average molecular weight (M n ) by size exclusion chromatography (SEC).Rates of moisture increase and Tg mix decrease were related to the decrease in PLGA M n through a modification of the Gordon-Taylor equation. Understanding the relative rates of polymer physical and chemical degradation will allow for improved design of PLGA formulations that control rates of drug delivery and preserve drug stability.

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Effect of Hydrolysis on the Strength of Hydrogen Bonds and T_g of Poly(vinylphenol-co-acetoxystyrene)

Cited by 19 publications

References 48 publications

Nucleobase Self-Assembly in Supramolecular Adhesives

Nucleobase Self-Assembly in Supramolecular Adhesives

Heat Capacity of Spider Silk-Like Block Copolymers

Physical properties of PLGA films during polymer degradation

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