Haward

Haward et al.t have reported some research in which a copolymer of styrene and hydroxyethylmethacrylate was cross-linked by hexamethylene diisocyanate. Draw the structural formula for a portion of this cross-linked polymer and indicate what part of the molecule is the result of a condensation reaction and what part results from addition polymerization. These authors indicate that the crosslinking reaction is carried out in sufficiently dilute solutions of copolymer that the crosslinking is primarily intramolecular rather than intermolecular. Explain the distinction between these two terms and why concentration affects the relative amounts of each. 

ELORY, p. J., Principles of Polymer Chemistry, Cornell University Press, Ithaca, New York (1953) HAWARD, R. N., Developments in Polymerisation, Vols 1 and 2, Applied Science, London (1979) JENKINS, A. D. (Ed.), Polymer Science (2 volumes), North-Holland, Amsterdam (1972)... 

Figure 16.10. Influence of styrene monomer content of the softening point and flow characteristics of polystyrene, (After Haward and Crabtee) ...

Bowden PB (1973) In Haward RN (ed) The physics of glassy polymers, Applied Science Publishers, London, p 279... 

HB Hopfenberg, V Stannett. Diffusion and sorption of gases and vapors in glassy polymers. In RN Haward, ed. The Physics of Glassy Polymers. New York Wiley, 1973, pp 504-547. 

Ahmad, Z. Ph.D. Thesis, University of Manchester, England, 1978. Stepto, R.F.T. "Developments in Polymerisation-III Haward,... 

To improve the ability to establish best practice with respect to manure use and prevention of pathogen transfer (especially on farms which are converting to organic farm management), a hazard analysis critical control point (HACCP)-based quality assurance system has been proposed (Haward and Leifert, 1999). This proposed four main critical control points (CCPs) (see Table 19.4). 

Table 19.4 Critical control points for HACCP-based minimisation of pathogen transfer risk associated with the use of manure-based fertilisers (Haward and Leifert, 1999)...

Dusek, K., Network formation by chain crosslinking (co)polymerization, in Haward, R. N. (ed.), Development in Polymerization, Vol. 3, Applied Science Publ., Barking, 1982, pp. 143-206. 

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