Poly growth rate

Although synthetic lubrication oil production amounts to only about 2% of the total market, volume has been increasing rapidly (67). Growth rates of the order of 20% per year for poly( a-olefin)s, 10% for polybutenes, and 8% for esters (28) reflect increasing automotive use and these increases would accelerate if synthetics were adopted for factory fill of engines by automotive manufacturers. The estimated production of poly( a-olefin)s for lubricants appears to be approximately 100,000 m /yr, esters 75,000, poly(alkylene glycol)s 42,000, polybutenes 38,000, phosphates 20,000, and dialkyl benzene 18,000 (28,67). The higher costs reflected in Table 18 (18,28) have restricted the volume of siUcones, chlorotrifluoroethylene, perfluoroalkylpolyethers, and polyphenyl ethers. 

The Cg—0 2 branched, odd and even, linear and internal olefins are used to produce improved flexible poly(vinyl chloride) plastics. Demand for these branched olefins, which are produced from propylene and butylene, is estimated to be increasing at a rate of 2% per year. However, the growth of the linear a-olefins is expected to slow down to a rate of 5% per year from 1992 to 1997 (3), as opposed to growth rates of 7—10% in the 1980s. 

Worldwide sales of poly(phenylene ether)—styrene resin alloys are 100,000—160,000 t/yr (47,96) aimual growth rates are ca 9%. Other resin, particularly acrylonitrile—butadiene—styrene (ABS) polymers and blends of these resins with PC resins, compete for similar appHcations. 

The lateral growth rate (V) of crystals of linear chain polymers strongly depends on molecular weight (M) [37]. Although the M dependence of V of folded chain crystals (FCCs) of polymers has been rather well studied, it is still an important unresolved problem. Magill et al. presented an experimental formula, V ocM-0-5, for poly (tetramethyl-p-silpenyline siloxane), poly (ethylene terephthalate), etc [38]. 

The specific growth rate (ji) becomes of interest for the poly(3HB) content if the poly(3HB) synthesis is growth-coupled. The possible content is then independent of time and is determined by the relation of qp to p. [74] ... 

The mesh plots show different slopes of productivity, depending on i and qp, and the poly(3HB) content. How an increase in i or qp enhances productivity is presented in Fig. 5, starting from two different pairs of actual jli and qp values. Each of the initial values was increased by 20% or 40%. If both specific velocities are increased, then the productivity increases in the same way. Starting from jli = 0.35 h 1 and qp = 0.15 g g 1 h 1 (A) optimization of the growth rate has a stronger effect over a broader range of final poly(3HB) contents than starting from jli = 0.2 h 1 and qp = 0.05 g g 1 h 1 (B). 

The medium composition used in the fed-batch process was optimized, resulting in cell densities near 100 g l-1. By using an exponential feed rate resulting in a growth rate of 0.05 h-1, a maximum biomass concentration of 112 g 1 1 was attained, with a biomass productivity of 1.8 g 1 1 h. The poly(3HAMCL) productivity however was low, 0.34 g 1 1 h, caused by a steady decrease of the poly(3HAMCL) content during the last part of the fermentation [51]. When this optimized medium composition was used in the continuous culture system described above, a maximum biomass concentration of 18 g 1 1 was reached. The PHA content however remained low at approximately 10% [51]. It is still unclear what causes these low PHA contents. 

Tant, M. R. and Culberson, W. T., Effect of molecular weight on spherulite growth rate of poly(ethylene terephthalate) via real-time small angle light scattering, Polym. Eng. Sci., 33, 1152-1156 (1993). 

Although the manufacture and sale of adhesives is a worldwide enterprise, the adhesives business can be characterized as a fragmented industry. The 1987 Census of Manufacturers obtained reports from 712 companies in the United States, each of which considers itself to be in the adhesives or sealants business only 275 of these companies had more than 20 employees. Phenolics, poly(vinyl acetate) adhesives, rubber cements, and hot-mclt adhesives arc the leading products in terms of monetary value. These products are used primarily in llie wood, paper, and packaging industries. The annual growth rate of the adhesives market is 2.3%, and individual segments of the market are expected to grow faster than this rate. 

Figure 2.13 Variation of the crystal growth rate with temperature for poly(ethy-lene terephlhalate), T , = 280°C. (From Ref. 11.)...

The aim of this paper is to consider ESC under not only the physical but also the chemical influence of the environment. In this case the chemical reactions (for example resulting in chain scission) are important and models based on solubility parameters are not valid. Hardly any literature is available on this subject. Moskala [10] reported chemical ESC of poly(ethylene terephthalate) (PET) in an aqueous sodium hydroxide (NaOH) solution. A discontinuous crack growth with an increased crack growth rate was found upon increasing NaOH concentration. However, one major drawback is that the effect of hydrolysis without external stress was not considered. Hydrolysis on its own can potentially lead to premature failures, whether or not the material is in a stressed or unstressed condition. 

Among these processes, only the Hock process and the toluene oxidation are important industrially. The other processes were discarded for economic reasons. In the Hock process acetone is formed as a by-product. This has not, however, hindered the expansion of this process, because there is a market for acetone. New plants predominantly use the cumene process. More than 95% of the 4,691,000 my (m = metric tonnes) consumed is produced by the cumene peroxidation process. Phenol s consumption growth rate of 3% is primarily based on its use in engineering plastics such as polycarbonates, polyetherimide and poly(phenylene oxide), and epoxy resins for the electronic industry. The Mitsui Company is, for instance, the world s second largest producer of phenol. Japan s production... 

Some materials can be produced only in amorphous or polycrystalline phase. For example, SCF precipitation of polymers such as poly(L-lactic acid)(PLLA) and proteins such as lysozyme and insulin have been widely investigated (see, e.g., Chapters 6, 9, and 10 in this book). These molecules form amorphous (proteins) or semicrystalline (PLLA) structures and typically have small values of both Ceq and tn, combined with a relatively large Tg constant (small growth rate). Similarly, organic or inorganic salts usually have very small Cgq and Tn constants. This explains why it is easy to produce very small (often submicrometer), spherical particles of these materials, al-... 

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