Effect of residual water and free volume on the glass-transition temperature and heat capacity in polystyrene/poly(vinyl acetate-co-butyl acrylate) structured latex films

2001 ◽  
Vol 39 (14) ◽  
pp. 1659-1664 ◽  
Author(s):  
M. Song ◽  
D. J. Hourston ◽  
G. G. Silva ◽  
J. C. Machado
Keyword(s):  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Vinyl Acetate ◽  
Free Volume ◽  
Butyl Acrylate ◽  
Residual Water ◽  
Latex Films

Study on Preparation and Properties of Pressure Sensitive Adhesive of Acrylate Prepared by Miniemulsion

2011 ◽  
Vol 183-185 ◽  
pp. 1938-1941
Author(s):  
Jiu Yin Pang ◽  
Chuan Sun ◽  
Shi Cheng Zhang ◽  
Zhen Xing
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Vinyl Acetate ◽  
Butyl Acrylate ◽  
Peel Strength ◽  
Excellent Performance ◽  
Pressure Sensitive Adhesive ◽  
Pressure Sensitive

Miniemulsion was prepared by means of different ratio of butyl acrylate with vinyl acetate emulsion pressure sensitive adhesive excellent performance. Focused on acrylic acid and vinyl acetate copolymers of different proportions of the glass transition temperature, molecular weight and molecular weight distribution of micro-factors, and build the macroscopic properties of the copolymer glass transition temperature and molecular weight between contacts. The use of APS as initiator under the conditions of the experiment found that with the increase of acrylic, PVC-floor, 180 peel strength composite materials decreased. While the molecular weight of butyl acrylate with the increase of the amount did not change significantly, the initial viscosity of the polymer and 180 º peel strength is improved, but the adhesive holding down quickly.

SILICON-CONTAINING OLIGOMERIC AZOINITIATORS IN THE SYNTHESIS OF BLOCK COPOLYMERS

2021 ◽  
Vol 43 (2) ◽  
pp. 123-132
Author(s):  
N.A. Busko ◽  
◽  
V.K. Grishchenko ◽  
A.V. Barantsova ◽  
N.V. Gudzenko ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Block Copolymers ◽  
Ir Spectroscopy ◽  
Molar Ratio ◽  
Capacity Curves ◽  
Azo Initiator ◽  
Azo Initiators

The aim of the work was to develop methods for the synthesis and study of the properties of silicon-containing oligomeric azo- and polyazoinitiators based on bis-γ-hydroxypropylpolysiloxane (HPS) and bis-γ-aminopropylpolysiloxane (APS). Silicon-containing oligomeric azoinitiators using HPS were synthesized on the basis of cyclohexanone azo-bis-isobutyrohydrazone (AGN-CH) and bis-γ-hydroxypropylpolysiloxane bifunctional macrodiisocyanate (MDIHPS). MDIHPS was obtained by the interaction of GPS with 2,4 toluene diisocyanate (2,4-TDI). Oligomeric azoinitiators have been obtained, which have the structure RXR and (RX)nR, where R is a propylpolysiloxane block, X is a azo initiator block. For the synthesis of an oligomeric azo initiator based on bis-γ-aminopropyl polysiloxane (APS), a method was first developed for the synthesis of a monomeric azo initiator with terminal oxadiazolinylcarbamanate isocyanate groups (AGN-NCO) by the interaction of AGN-CH and 2,4-TDI at a molar ratio of 1: 2. On the basis of the obtained AGN-NCO and APS at a molar ratio of AGN-NCO: APS = 1: 1, an oligomeric azo initiator (OAI APS-P) was synthesized, which has the structure (RX)nR, where R is a propylpolysiloxane block, X is an azo initiator block. The structures of monomeric and oligomeric azo initiators have been studied by UV and IR spectroscopy, and the kinetic regularities of their synthesis have been calculated. On the basis of oligomeric azo initiators and styrene, block copolymers of the (AB)nA type were obtained by the method of thermal and photoinitiated radical polymerization, where A is a propylpolysiloxane block, B is an oligosyrene block with a constant value of the organosilicon block and a different size of the oligostyrene block. The structure of block copolymers was investigated by IR spectroscopy. It was shown that during photopolymerization, oligostyrene blocks of shorter length are formed than during thermopolymerization, and possible oxidation processes. The study of relaxation transitions by DSC in oligostyrene and propylpolysiloxane blocks of the BCP showed that the common heat capacity curves are the presence of two jumps in the heat capacity at the glass transition temperatures of the polysiloxane and oligostyrene microphase. A slight shift in the glass transition temperature of polysiloxane microphases in BCP towards higher temperatures compared to the homopolymer may be associated with the effect of oligostyrene microphase. With a decrease in the length of the oligosyrene block, a low-temperature shift in the glass transition temperature of oligostyrene blocks relative to the homopolymer and a depression of ∆Cp,2 are observed, which is associated with the suppression of mobility in oligodienic microphases by less mobile propylpolysiloxane blocks.

scholarly journals Differential Scanning Calorimetry for Determining the Thermodynamic Properties of Selected Honeys

2015 ◽  
Vol 59 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Sławomir Bakier ◽  
Kamila Goderska ◽  
Krzysztof Mansfeld
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermodynamic Properties ◽  
Sugar Content ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Complete Liquefaction

Abstract Thermodynamic properties of selected honeys: glass transition temperature (Tg), the change in specifi c heat capacity (ΔCp), and enthalpy (ΔH) were analysed using differential scanning calorimetry (DSC) in relation to the composition i.e. water and sugar content. Glass transition temperatures (Tg) of various types of honey differed significantly (p<0.05) and ranged from -49.7°C (polyfloral) to -34.8°C (sunflower). There was a strong correlation between the Tg values and the moisture content in honey (r = -0.94). The degree of crystallisation of the honey also influenced the Tg values. It has been shown that the presence or absence of sugar crystals influenced the glass transition temperature. For the decrystallised honeys, the Tg values were 6 to 11°C lower than for the crystallised honeys. The more crystallised a honey was, the greater the temperature difference was between the decrystallised and crystallized honey. In conclusion, to obtain reliable DSC results, it is crucial to measure the glass transition after the complete liquefaction of honey.

Effects of sequence length distribution on heat capacity and glass transition temperature of styrene—methyl methacrylate copolymers

Polymer ◽  
1994 ◽  
Vol 35 (17) ◽  
pp. 3698-3702 ◽  
Author(s):  
Hidematsu Suzuki ◽  
Yoshiyuki Nishio ◽  
Noritaka Kimura ◽  
V.B.F. Mathot ◽  
M.F.J. Pijpers ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Methyl Methacrylate ◽  
Length Distribution ◽  
Sequence Length ◽  
Methacrylate Copolymers
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