Polymethyl methacrylate modulus

The data provided by Toyota Research Group of Japan on polyamide-MMT nanocomposites indicate tensile strength improvements of approximately 40%-50% at 23°C and modulus improvement of about 70% at the same temperature. Heat distortion temperature has been shown to increase from 65°C for the unmodified polyamide to 152°C for the nanoclay-modified material, all the above having been achieved with just a 5% loading of MMT clay. Similar mechanical property improvements were presented for polymethyl methacrylate-clay hybrids [27]. 

Fig. 5.11. Plateau modulus vs. concentration for polymethyl methacrylate 0 (142) and cis-polyisoprene (167). The solid points are undiluted samples...

TABLE 1. Storage modulus testiug of homopolymers aud a-acetoxyacrylate copolymers. Polymethyl methacrylate is provided as a reference. 

Non-0-SoIutions. A number of data have been published for the intrinsic complex modulus of flexible polymers in good solvents. Tanaka, Sakanishi and coworkers studied the system of PIB in cyclohexane (2,92,98), polymethyl methacrylate (PMMA) in chloroform (2,9/), PMS in benzene and in toluene (94,99) and a few copolymers of styrene-butadiene in toluene and in cyclohexane (100). Schrag, Ferry et al. reported the results on PS in a-chloronaphthalene and in a chlorinated diphenyl (3), polybutadiene (PBD) in a-chloronaphthalene and in Decalin (101) and PMS in Decalin and in a-chloronaphthalene (102). In all these cases, the frequency dependence of the intrinsic complex modulus is qualitatively described as more Rouse-like as compared with the results for -solutions. Apart from the physical appropriateness, any of the three versions of the Zimm theory can be applied to the experimental results the original Zimm integrodifferential equation... 

Figure 13.28 Shear modulus (a) and damping (b) at 1 Hz as a function of temperature for poly(n-alkyl methacrylate). (---) Polymethyl methacrylate (-) polyethyl methacrylate (----) poly(n-propyl meth-...

Experimental and theoretical tensile modulus as a function of volume fraction of ethylene methacrylate (EMA) phase in polymethyl methacrylate (PMMA)/EMA blends. 

Influence of Chemical Aging on Tensile Modulus of Polymethyl Methacrylate (PMMA) and Its Blends with Ethylene Methacrylate (EMA)... 

Effect of ethylene methacrylate (EM A) content on storage modulus of polymethyl methacrylate (PMMA) blends. 

Figure 8.30. The dilational modulus (a) and dilational viscosity (b) as functions of the surface concentration for a graft copolymer of polymethyl methacrylate and polyethylene oxide spread at the air/water interface. After Peace etal. (1998).

Crystallinity plays a large role in the physical behavior of polymers. The amorphous regions play perhaps an even greater role. Some amorphous polymers such as polymethyl methacrylate (PMMA) are stiff, hard plastics at room temperature, whereas polymers such as polybutadiene are soft and flexible at room temperature. If PMMA is healed to lOS C, it will soften, and its modulus wiU be reduced by orders of magnitude. If polybutadiene is cooled at to —73 C, it will become stiff and hard. The temperature at which this hard-to-soft transformation takes place is called the glass transition temperature T. ... 

Polymethyl Methacrylate. When PMMA is cast into sheets and lenses, addition of a glycol dimethacrylate comonomer produces cross-Unking, which increases modulus, abrasion-resistance, heat... 

Figure 9.1 Temperature dependence of loss modulus G2 for polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), poly-n-propyl methacrylate (P-n-PMA) and poly-n-butyl methacrylate (P-n-BMA). (Reproduced with permission from Heijboer, in The Physics of Non-crystalline Solids, North-Holland, Amsterdam, 1965, p. 231)...

Hu et al. [159] studied the viscoelastic properties of silica-polymethyl methacrylate nanocomposites. These nanocomposites exhibited higher storage and loss modulus than those of pristine polymethyl methaaylate. 

We have reported [66] a limited study of spread polymethyl methacrylates and polyethylene oxide. Figure 12.19 shows the variation in surface tension, shear viscosity and dilational modulus obtained from SQELS data as a function of surface concentration. The viscoelastic moduli both show maximum values at finite values of the surface concentration. As the capillary waves generate oscillatory stress and strain, these are related via the complex dynamic modulus of the surface... 

Figure 12.19 Derived parameters from surface quasi-elastk light scattering as a function of concentration of polymethyl methacrylate spread on water (a) surface tension (b) surface shear viscosity (c) dilational modulus...

The influence of molecular entanglements is illustrated by Figure 7.3, which shows the stress relaxation behaviour for two samples of polymethyl methacrylate. It is seen that the lower molecular mass sample does not show a rubbery plateau region of modulus but passes directly from the viscoelastic region to the region of permanent flow. 

Storage modulus versus frequency for the same 84 nm polymethyl methacrylate dispersions as shown in Figure 10.6.2 at several etr- r Frith et al. (1990). 

Plastics with stress-strain curves of the type in Fig. 20.1a are rigid and brittle. The former term refers to the high initial modulus. The latter refers to the area under the stress strain curve, which represents the energy per unit volume required to cause failure. These materials usually fail by catastrophic crack propagation at strains on the order of 2%. Since Wdness correlates well with tensile modulus, it is another valuable property of this type of plastic. Examples of this class are polystyrene, polymethyl methacrylate, and most thermosets. 

Fig. 2.13. Complex dynamic tensile modulus of blends (solid line) and graft copolymers (circles) respectively of polymethyl-methacrylate (75% by weight) and polybutylacrylate (25% by weight) at 110 Hz (after [75, 761).

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