ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 6 doc

... r1 and r2are the ionic radius of cation and anion, respectively, and e is the electron charge. This relation shows that by increasing the apparent ionicradius of the cation and that of the ... radius of the lithium ion; the attack of carbonyl groups by ion pairs can thus be thwarted, the probability of terminationreduced, and the control of polymerization improved in this way.8 .6. 6.2. ... comparison of apKa of 41 with that of water which is the conjugated acid of metal hydroxidesgives an idea of the very high reactivity of the conjugate base. This imposesthat monomers are free of...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 1 docx

... transitions and relaxations of polymers, their mechanical properties and their rheology. These thirteen chapters are rounded off by monographs (chaptersXIV to XVI) of natural polymers and of some ... and degradation of covalent bonds and formation of small molecules. The measurement of Ecorequiresthe use of indirect methods such as the comparison of swelling or dissolution inliquids of ... because of theextreme variability of the polymer properties and the endless utilization of polymers, particularly in the ﬁeld of materials. However, one can identify three main cate-gories of polymers...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 7 docx

... REACTIVITY AND CHEMICAL MODIFICATION OF POLYMERS degradation by depolymerizationmtMntdegradation by random chain breakingmttMnFigure 9.2. Variations of both molar mass and mass of polymer ... use of techniques of high sensitivity and precision such as mass spectrometry (MALDI-TOF) is helpfulwith respect to the identiﬁcation of these functional groups.10.3. BLOCK AND GRAFT COPOLYMERSAs ... eight-shapedbicyclics, and so on.10.4.2. Star Polymers Comb-like polymers (see Section 10.3.2), whose backbone is of small degree of polymerization, tend to adopt a conformation that reminds that of star polymers; as...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 2 ppt

... ÷(α5−α3)4πs2033/2F(Y) (4 .63 )withY = 2(α2−1) (4 .64 )The expressions (4 .62 ) and (4.53) show that the radius of gyration of a chainsubjected to the phenomenon of excluded volume is proportional ... uafter n steps is the product of the probability of having a sequence of n+positivemoves and n−negative moves, each one of probability 1/2 times the number of ways of executing n+positive ... the mixing and also the existence of lower and highercritical temperatures of phase separation when there is a great disparity in the size of components 1 and 2. At high pressure and/ or low...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 3 ppsx

... the mass of the solute, V1 and V2are the volumes occupiedby the solvent and the solute, N1 and N2are the number of molecules of solvent and solute, and M2is the molar mass of the solute.One ... characteristic textures of the various mesophases; he can also make use of differential scanning calorimetry and of X-ray diffraction.1 56 DETERMINATION OF MOLAR MASSES AND STUDY OF CONFORMATIONS & ... ma,mc,andm denote the mass of the amorphous and crystallinephases and the total mass phases, respectively.IfVc, V,ρc, and ρ are the bulk volumes and the densities of the crystallinephase and...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 4 pptx

... polymer including x points of branching of functionality f and p grafts,we obtaing =6p2+(f − 1)x(x2−1)6p(p +1)(p +2) (6. 64)with p =(f −1)x. 6. 4.4. Techniques of MeasurementIt is imperative ... X and vice versa, pX and pYare related by the equation4X4pX= 2NYpY2 06 DETERMINATION OF MOLAR MASSES AND STUDY OF CONFORMATIONS & MORPHOLOGIESTable 6. 2. Enthalpy of melting of ... prior establishment of a calibra-tion curve from elution volumes of standard samples as a function of their molarmass. Standard samples of polystyrene for polymers soluble in organic solventsor...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 5 potx

... char-acter and afford chains and architectures of controlled size and structure are in greatdemand. Among the speciﬁc characteristics, one can mention a low dispersity of chains. Such a narrowing of ... Probability (Ptr) of formation of i, h,ands triads, according to Bernouillian statistics.In Figure 8.1 are plotted the variations of the probabilities of existence of thevarious types of triads against ... alow value of the energy of activation of the process (Ea∼10 kJ·mol−1).Table 8.8. Rate constants of termination by combination(ktc) for some vinyl and related monomers, at 60 ◦CMonomer...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 8 ppsx

... units up to the overall movement of the chain,through the use of a suitable analytical technique. Organic and Physical Chemistry of Polymers, by Yves Gnanou and Michel FontanilleCopyright  ... FORMULATION, AND POLYMER PROCESSING TECHNIQUEStwo models, that of Rouse and that of reptation, thus differ by their description of both the diffusion and the viscosity of polymer melts. The viscosity of ... extrusion, and injection moldingimply very high rates of shearing with a value of about 102,105, and 107s−1,respectively. The decrease of η with high values of ˙γ enables high rates of pro-duction....

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 9 ppt

... degree of crystallinity lies between 0.4 and 0 .6. VINYL AND RELATED POLYMERS 535for the formation of small-size crystallites (“discs” of ∼1 nm thickness and ∼4nmdiameter), which are zones of strong ... bases (one internal and one external) to attain rates of mm triadsclose to 99% and activities (see deﬁnition in Section 8.8.2) of several hundreds of grams of PP per gram of Ti per h pe MPa.Although ... poly(but-1-ene) and poly(4-methylpent-1-ene) have attained theindustrial level. Organic and Physical Chemistry of Polymers, by Yves Gnanou and Michel FontanilleCopyright  2008 John Wiley & Sons, Inc.513POLY(CONJUGATED...

ORGANIC AND PHYSICAL CHEMISTRY OF POLYMERS phần 10 ppt

... 4 76. Enthalpy of polymerization: 251–253,274, 310, 3 36. Enthalpy of mixing: 50, 55–57, 62 63 , 66 , 78, 82, 83.Entropy of mixing: 50–54, 57, 62 , 63 , 65 68 , 78, 82–84, 86, 149, 1 96. EPDM (elastomer): ... 395–398.Ideal solutions: 50, 54, 55, 66 .Initiation, Initiators (of polymerizations):249, 250, 2 56 258, 260 , 262 , 263 , 265 , 266 , 268 –274, 278–280,282–2 86, 288–294, 302–307,309–317, 322–327, ... 561 , 567 ,573.Extent of reaction: 217–220, 224, 225,227, 259, 268 , 280, 360 , 362 , 363 ,584.Extrusion, Extruder: 1 36, 403, 471, 478,482, 483, 4 86 488, 490, 518, 520,537, 540, 541, 550, 561 ,...

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