Poly testing biodegradability

Biodegradable poly(phosphoester-urethanes) containing bisglycophosphite as the chain extender were synthesized. Methylene bis-4-phenyl isocyanate (MDI) and toluene diisocyanate (TDI) were initially used as diisocyanates. Since there was a concern that the degradation products could be toxic, the ethyl 2,6-diisocyanatohexanoate (LDI) was synthesized and replaced the MDI (or TDI). The hydrolytic stability and solubility of these polymers were tested. Preliminary release studies of 5-fluorouracil from MDI based poly(phosphoester-urethane) and methotrexate from LDI based poly(phosphoester-urethane) are also reported. 

Figure 10.17 Biodegradation rate curves for poly(vinyl alcohol) with adapted and non-adapted inoculum according to the Sapromat test [212]...

In our group, several dendrimers based on ( R)-3-hydroxybutanoic acid (HB) have been prepared [56-58]. The dendrimers were synthesized by the convergent strategy. Trimesic acid has been used as core unit and the benzyl esters of the dimer and the tetramer of HB as elongation units. In such a way dendrimers of 1st and 2nd generation (27-30) have been constructed (Fig. 13). Since poly(.R)-3-hydroxybutanoic acid (PHB) is known to be biodegradable [59, 60] the stability of the dendrimers 27-30 was tested in the presence of PHB-de-... 

Table I shows the five-day biochemical oxygen demand (BOD5 ) of some poly(sodium carboxylate)s and poly(vinyl alcohoDs (PVA). The BOD5 test according to JIS K 0102 is only an indication of susceptibility of products to biodegradation, but the test is often an useful tool for rapid screening. As shown in Table I, PMLA and...

Soil biodegradation tests were done by taking a sandy loam as the source of the soil micro-organisms. All polymer samples were sieved through ASTM sieves and all the samples except poly-e-caprolactone, had a particle diameter between 90 and 53 pm, Poly-e-caprolactone sample was prepared dissolving a commercially... 

PVA films buried in soil were tested after 120 days and showed only very limited signs of biodegradation, and even field tests with PVA sheets buried for 2 years in different natural soil sites showed only limited (10%) weight loss. No traces of colonising microorganisms were detected on the incubated material. Degradable polymers like poly(hydroxy butyrate), PCL or starch are usually extensively... 

In pursuit of a chlorine-resistant, non-biodegradable thin-film-composite membrane, Cadotte et al. 97 )03,104 fabricated interfacially the poly(piperazineamide) membrane (NS-300). The interfacially formed piperazine isophthalamide and terephthalamide membranes exhibited high salt rejection (98 %) in sea water tests but their flux was low (Table 8). The replacing of the isophthaloyl chloride with its triacyl chloride analog, trimesoyl chloride improved vastly the flux of the membrane but its seawater salt rejection was low — in the range of 60 70 % (55). The trimesoyl... 

Low viscosity poly(a-olefins), e.g., 2 and 4 cSt, can be classified as relatively biodegradable in aqueous systems as defined by the CEC L-33-A-93 test however, this does not mean that all poly(a-olefins) are biodegradable. The concept of biodegrability is very difficult to define. The extremely low water solubility of poly(a-olefins) decreases the available surface area for bacterial degradation. If high biodegrabilities are required, linear polyol esters tend to be used. 

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