Without accelerators

Initially, vulcanization was accomplished by heating elemental sulfur at a concentration of 8 parts per 100 parts of rubber (phr) for 5 h at 140°C. The addition of zinc oxide reduced the time to 3 h. Accelerator in concentrations as low as 0.5 phr have since reduced time to 1-3 min. As a result, elastomer vulcanization by sulfur without accelerator is no longer of commercial significance. An exception is the use of about 30 or more phr of sulfur, with httle or no accelerator, to produce molded products of hard mbber called ebonite. 

If all went well, the conductivity rose from the initial, very low, level without acceleration to a maximum and constant value in less than ca 5 seconds (90% in 3 seconds), and this time was the best-possible indication that the speed of mixing-in of the initiator was adequate. Further, it shows that the rate of initiation was also great enough, because if this had been too low, the initially high conductivity would have fallen noticeably as the small, fast initiating cations were replaced by the large, slow oligomeric and polymeric cations. 

Figure 8. Biodegradation of photodegraded LDPE. Cpm released (as C-CO2) demonstrates decomposition of the low molecular weight fraction of the plastic. Line A LDPE with accelerant of photodegradation Line B LDPE without accelerant. Maximum cpm released is less than 5% of total cpm added as LDPE. Data are from (45), Table 5.

The chemical composition of these accelerators is neither described in the pertinent bibliography nor divulged by their producers. They have a pH between 3 and 5.5 and an alkali content of less than 0.3% and are used in amounts between 3 and 10% by weight of cement. When used in adequate amounts, they allow overhead buildup in linings of up to 300 mm thick. An important characteristic of these accelerators is that the latter-age strengths are not reduced when compared with a reference material (without accelerator) [108], For example, in the construction of the tunnels of the south freeway (Via Express Sul) in Florianopolis, Brazil, comparative tests were made with an alkali-free liquid accelerator and the sodium-aluminate-based accelerator. The aluminate-based accelerator was added in an amount... 

E (1) Accelerates reaction through lowered AS achieved by restricting configurational space of starting materials (2) Increases yield without acceleration by inhibiting alternative reactions (normal topochemical control) Yes... 

Compaction has little effect on the suspensibility of DDT powders when tested without accelerated-storage pretreatment however, when tested after accelerated-storage pretreatment, the suspensibility decreased with increasing compaction. The aged powders, although tested without heat treatment, exhibited the same pattern of loss of suspensibility with increased compaction as did the fresh powders after the accelerated-... 

Phosphite functionality reduces epoxy viscosity without accelerating cure... 

Within the past several decades, considerable field work has been done using sodium silicate solution and organic reactants without accelerators. Much of this relates to vehicular tunnels in the Washington, D.C. area and is well documented [8]. Contractors field charts demonstrate gel times of the grout in Fig. 11.5. 

Castings cured with the commercial aromatic amine derived from aniline-formaldehyde were prepared like the HHPA-cured castings, but without accelerator. The aromatic amine mixture was about 90% methylenedianiline (MDA) and tended to partially... 

Initially, as the particle begins to fall, its velocity increases. Eventually a point is reached at which the increasing resistance force equals the constant downward force, and the particle then continues to fall without acceleration at a constant velocity, known as terminal velocity vt. The downward force due to gravity... 

Deferred Income Taxes. Deferred income taxes are encouraged by the government as a tax incentive that will benefit the economy. An example of such an incentive is accelerated depreciation, which provides the rapid write-off in the early years of an investment. The net effect is to reduce what the company will pay in current taxes, but the full amount must be paid in the future. To smooth out wide fluctuations in a company s earnings, an entry is made for deferred taxes. This entry shows what the taxes would be without accelerated depreciation write-offs. 

It has been found by further investigation that there is apparently another step in the fermentation reaction in which the dextrose di-phosphate splits into two moles of triose mono-phosphate. It should be particularly noted that the immediately preceding study of the mechanism of the action of yeast juice is not directly applicable to the action of yeast. E.gSlator (loc. cit.) found that phosphates are without accelerating effect when living yeast cells are employed. 

If the interface is stationary, or if it translates without accelerating, then a steady-state force balance given by equation (8-180) states that the sum of all surface-related forces acting on the interface must vanish. Body forces are not an issue because the system (i.e., the gas-liquid interface) exhibits negligible volume. The total mass flux vector of an adjacent phase relative to a mobile interface is... 

Maintenance or storage media maintains the viability and physiological characteristics over a period of time without accelerating growth it contains only the basic nutrients. Substances which enhance growth or substances which when degraded result in the production of harmful substances, such as acids and so on., are omitted. 

Quickset in range 120-150°C for hot-press g h molding SMC or BMC can be accelerated by promoters. Special for SMC/BMC at 130-160°C without accelerator not sensitive to fillers pigments and promoters... 

Standard type for SMC/BMC at 130-160°C HI can be accelerated by promoters sensitive to some fillers and pigments (e.g. carbon black). Standard for granulated molding compounds at 130-160 C without accelerator can easily be mixed in as free-flowing powder... 

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