Tokyo Metropolitan Industrial Technology Research Institute

Controlling the concentrations of chems. in the plating line is important.In most cases, such control is achieved using chem. anal., which is difficult to perform rapidly because of the large amounts of manual work involved.To resolve this difficulty, a calculation method for concentration estimation was evaluated for this study.Estimation was performed by adding or subtracting changes in concentration caused by solution transfer, rinsing, and evaporation from the initial concentrationAfter detecting the equations for calculating each concentration change, a concentration estimation program was created by combining these equations.Verification of the program using a simulated process revealed that the estimated values capture changes in the measured values, but some discrepancy exists between the estimated values and the measured values.This discrepancy might be attributable to the fact that the concentration calculations do not incorporate diffusion effects.Moreover, the drag-in solution might not be mixed sufficiently with the destination solutionTherefore, the exptl. was conducted using a barrel, which was more likely to achieve sufficient mixing.The concentrations in all processes were then estimated correctly.These findings indicate that chem. concentrations during plating and rinsing processes can be estimated by calculationThis inexpensive method, which is applicable to widely diverse processes and chems., can facilitate control of concentrations during plating processes.

To assess the biodegradability of plastic materials in the marine environment, standard test methods based on uniform standards have been established by organizations such as ISO (International Organization for Standardization) and ASTM (American Society for Testing and Materials).These test methods include 'field tests', which are carried out in the actual sea area, and 'laboratory tests', which are carried out in the laboratory environments that simulate various marine situations.Essentially, plastics materials are assumed to undergo biodegradation through the same degradation mechanisms, whether in the laboratory environment or in the actual marine environment.However, in laboratory tests, small amounts of seawater are sealed in test vials and employed for several months or more without replacement, raising concerns that changes in the condition of seawater, including micro-organisms, may affect the degradation mechanisms of plastic materials.In this study, the biodegradation behavior of poly(glycolic acid) (PGA) film immersed in seawater was taken as an example, and the influence of the test environment on the biodegradation mechanism of PGA film was examined through the anal. of degradation residues in laboratory and field tests.Our results revealed that the PGA films immersed in seawater undergo hydrolysis via a non-enzymic bulk erosion mechanism that proceeds preferentially in the amorphous regions, in both laboratory and field tests.

Simplification of the measurement method for biobased carbon content was achieved by applying CO2 capture with ethylenediamine as a pretreatment for liquid scintillation counting (LSC) measurement.The biobased carbon content can be determined by a new method based on comparison between radiocarbon count rates of carbamic acid derivatives synthesized with reference materials of biomass carbon and petroleum carbon, although LSC measurements were performed for radiocarbon in solid-state carbamic acid derivativeCross-checking with the Accelerator Mass Spectrometry (AMS) method confirmed that this method is sufficiently accurate, so it is expected to be used as a screening method.