摘要:

This work presents an experimental investigation on the response of unscrimmed FM‐73 adhesive to mechanical loads under constant environment. The nonlinear, viscoelastic behavior of the material was characterized by means of isothermal uniaxial creep and recovery data, which are inserted into a constitutive equation for uniaxial loading. The model was then extrapolated to anticipate the response of the material under two‐step loading as well as to predict the hysteresis loop under cyclic constant stress rate tests. Excellent agreement was found between predicted values and corresponding experimental results obtained in subsequent tests.

ISSN:0148-6055    

DOI:10.1122/1.549666

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

摘要:

A new kinetic theory has been proposed in which the formation of structure is assumed to take place in two processes. Combining structural parameters of the model with the viscosity, the variation of shearing stress with time for rheopectic suspensions has been described. A good agreement was obtained between theoretical predictions and experimental results obtained for suspensions of titanate fibers in a polymer solution. Rate constants for both the formation and breaking of network structure were evaluated as functions of rate of shear. The theory was also applied to a suspension of polystyrene particles investigated by Gadala‐Maria and Acrivos to evaluate rate constants. The dependence of the rate constants on rate of shear was found to be different from that for suspensions of titanate fibers.

ISSN:0148-6055    

DOI:10.1122/1.549667

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

摘要:

A survey is given of the kinetic theories for polymer solutions and polymer melts, with emphasis on the derivation of constitutive equations. Forsolutionsthe discussion is divided into two parts: (i) the elementary dumbbell models, which provide considerable information about nonlinear rheological behavior without much expenditure of mathematical or computational effort, and (ii) the freely jointed chain models, which are more realistic. Formeltstwo kinds of theories are compared: (i) the older Gaussian network theories, and (ii) the newer reptating chain theories. The most successful constitutive equations now available are those derived by, or at least inspired by, molecular theories.

ISSN:0148-6055    

DOI:10.1122/1.549668

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

摘要:

A study was made of the cone‐plate and parallel plate rheometry of two polymer solutions in order to obtain the viscometric functions τ,N1,and−N2by different methods. It is shown that it is possible to determine−N2by using normal stress data from the cone‐plate and parallel plate flows. A comparison of this−N2data with a more accurate method has shown good agreement. There is good agreement also between τ data from the cone‐plate and parallel plate flows. An analysis of some of the sources of error in cone‐plate and parallel plate rheometry has shown that for the current experiments on the Instron 3250 rotary rheometer, inertial effects, and changes in the cone‐plate or parallel plate gap during testing are insignificant. It is shown that the vertical force in the parallel plate rheometer depends on the parallel plate gaph, the force showing a plateau above a critical gaphc.From this work it was foundhc/R∼0.05.The shear stress is unaffected by the gap. At this stage there is no known mechanism for this effect. For a 1.1% polyisobutylene solution it was found−N2/N1=0.11±0.03and for a 7.14% polystyrene solution−N2/N1=0.31±0.05.These values agree with literature values for polystyrene and polyisobutylene solutions. For a given polymer,−N2/N1is only weakly dependent on the polymer concentration.

ISSN:0148-6055    

DOI:10.1122/1.549684

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.549685

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.549669

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.549670

出版商:The Society of Rheology    

年代:1982

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.549692

出版商:The Society of Rheology    

年代:1982

数据来源: AIP