The NMR of Polymers

Slonim, I. Ya.; Lyubimov, A. N.

doi:10.1007/978-1-4684-1773-9

Cited by 2 publications

(2 citation statements)

References 307 publications

(522 reference statements)

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“…Pada saat nilai dari waktu relaksasi spin-kisi (T1) naik terjadi pembentukan ikatan silang akibat irradiasi neutron, sebaliknya pada saat nilai T1 turun terjadi pemutusan ikatan silang akibat irradiasi neutron. Terjadinya pemutusan ikatan silang yang terbanyak pada saat T1 paling minimum dan terjadi pembentukan ikatan silang terbanyak pada saat nilai T1 paling maksimum [11]. Efek irradiasi neutron pada molekul polimer PVC mengakibatkan perubahan warna yang lebih menggelap, ini disebabkan terjadinya pelepasan HCl dari rantai molekul polimer PVC [3].…”

Section: Interaksi Radiasi Neutron Dengan Materiunclassified

Pengaruh Radiasi Neutron Terhadap Waktu Relaksasi Spin-Kisi (T1) Pada Polimer Polivinil Klorida (Pvc) dengan Spektroskopi Nmr Pulsa

Susilawati¹

2017

J. Pendidik. Fis. Teknol.

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Abstract.A research measurement of spin-lattice relaxation time (T1) with a pulse NMR spectrometer as well as a test of strength (tensile test and compression test) polymer material PVC (Poly Vinyl Chloride) with tools united-1 test system SFM SFM-30. The study aims to investigate the influence of the neutron fluence on the spin-lattice relaxation time (T1) and to determine the PVC polymer material strength test. On the measurement of the spin-lattice relaxation time (T1) 16 n/cm 2 , the average value of the minimum σ is (9.5± 0.1) MPa for tensile test, and the average value is the minimum σ (38.4±0.1) MPa for compression test. Value of the maximum power of the PVC polymer materials at fluence 60.98x10 16 n/cm2, the average value of the maximum σ is (43.2±0.9) MPa for tensile test and the average value of the maximum σ is (55.4±1.1) MPa for compression test. Keywords: neutron radiation, relaxation time, the polymer PVC PENDAHULUANResonansi Magnetik Inti yang disingkat dengan RMI atau NMR (Nuclear Magnetik Resonance) dikemukan oleh Bloch pada tahun 1946 yang merupakan salah satu alat fisika yang banyak digunakan untuk penelitian dibidang fisika. Selain penelitian dibidang fisika NMR dapat juga digunakan dalam penelitian pada bidang kimia, industri, pertanian, farmasi dan kedokteran. Alat spectrometer NMR ini pada prinsipnya bekerja berdasarkan resonansi antara momen magnet inti atom yang berputar dengan prosesi larmor dengan gelombang radio yang dikenakan padanya. Tehnik pengukuran NMR yang akan ditelaah yaitu tehnik NMR pulsa yang dikembangkan oleh Hahn [6]. Prinsip kerja NMR pulsa berdasarkan pada perubahan medan osilasi frekuensi radio secara pulsa. Perubahan medan osilasi secara pulsa akan menghasilkan perubahan amplitudo sinyal yang dapat digunakan untuk menentukan waktu relaksasi spin-kisi (T1) yang merupakan kajian penting dalam penelitian ini.Waktu relaksasi dapat memberikan gambaran karakteristik dari cuplikan yang dijadikan objek penelitian. Jenis cuplikan yang berbeda akan memberikan waktu relaksasi spin-kisi (T1) yang berbeda. Hal ini disebebkan oleh perlakuan magnetisasi dari momen magnet setiap cuplikan. Waktu relaksasi spin-kisi (T1) berhubungan dengan perpindahan tenaga antara spin dengan lingkungannya, yang didefinisikan sebagai waktu terjadinya orientasi momen magnet dari sistem acak ke pengutuban yaitu sejajar dengan medan magnet luar B0, sehingga mencapai keadaan setimbang dalam medan tersebut.Tehnik pengukuran waktu relaksasi dengan NMR pulsa ini, instrumennya dikontrol oleh mikroprosesor sehingga bekerjanya alat ini dapat dikerjakan secara otomatis. Sistem deteksinya lebih cepat sehingga sangat peka untuk mempelajari sifat-sifat bahan baik berupa zat padat maupun zat cair dengan tidak merusak sampel dari bahan penelitian.

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Section: Interaksi Radiasi Neutron Dengan Materiunclassified

Pengaruh Radiasi Neutron Terhadap Waktu Relaksasi Spin-Kisi (T1) Pada Polimer Polivinil Klorida (Pvc) dengan Spektroskopi Nmr Pulsa

Susilawati¹

2017

J. Pendidik. Fis. Teknol.

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“…The 1 H NMR spectrum of the polymer shows a peak of two magnetically equivalent protons of methylene group at 2.1 δ ppm (Fig. 10) indicating the syndiotactic29 nature of the polymer. The acrylate protons appear as triplet at 3.5 δ ppm.…”

Section: Spectral Analysismentioning

confidence: 99%

Understanding social obstacles to early breast cancer detection is critical to improving breast cancer outcome in low‐ and middle‐resource countries

Anderson

2010

Cancer

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In most low-and middle-resource countries (LMCs), breast cancer incidence rates are increasing more rapidly than in regions where incidence rates already are high. Despite the younger age structure of most developing countries, LMCs already account for 45% of the incident breast cancer cases and cause 54% of the annual breast cancer deaths around the globe. 1 Even assuming (conservatively) that there will be no change in underlying age-specific rates, a nearly 50% increase is anticipated in breast cancer global incidence and mortality between the years 2002 and 2020 caused simply by the aging of current global populations. These rising cancer rates will be disproportionately greater among countries in the developing world, and the rates in LMCs are projected to reach a 55% increased incidence and a 58% increased mortality in <20 years. 1 In reality, these projected statistics probably underestimate future cancer rates, because the few data available from LMCs reveal increasing age-specific breast cancer incidence and mortality rates, especially among recent birth cohorts. This is especially true for urban women in LMCs and is attributable in part to the adoption of Western lifestyles. 2,3 Improvements in breast cancer survival in the industrialized world that have been observed in recent decades can be attributed to early detection by screening combined with timely and effective treatment as guided by the results of extensive and rigorously performed clinical trials. 4 Randomized trials of screening mammography combined with clinical breast examination (CBE) initiated in the 1970s demonstrated that early cancer detection within a given population leads to down-staging of disease and improvement in breast cancer survival. At the same time, randomized trials of systemic therapies for breast cancer proved that endocrine therapy for estrogen receptor (ER)-positive cancers and cytotoxic chemotherapy for ER-negative cancers improve survival and produce durable long-term cure among patients with lymph node negative, lymph node positive, and even locally advanced breast cancers. 5 Breast cancer mortality essentially was unchanged in the United States for 6 decades between 1930 and 1990. By contrast, since 1990, age-adjusted breast cancer mortality has been dropping by nearly 2% each year in the United States, indicating that true progress is being made in the management of this disease. 6 Similar improvements also are being observed in Western European countries that have invoked population-wide early detection and adjuvant treatment programs.Notably, minority women in the United States are more likely to present with advanced stage disease and have higher mortality rates than white women, although white women and black women who present with similar stage disease and receive similar treatment have similar outcomes. These findings suggest that differences in stage at presentation should represent a primary target for research, the goal of which is to determine which interventions best reduce disparities in cancer outcom...

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The NMR of Polymers

Cited by 2 publications

References 307 publications

Pengaruh Radiasi Neutron Terhadap Waktu Relaksasi Spin-Kisi (T1) Pada Polimer Polivinil Klorida (Pvc) dengan Spektroskopi Nmr Pulsa

Pengaruh Radiasi Neutron Terhadap Waktu Relaksasi Spin-Kisi (T1) Pada Polimer Polivinil Klorida (Pvc) dengan Spektroskopi Nmr Pulsa

Understanding social obstacles to early breast cancer detection is critical to improving breast cancer outcome in low‐ and middle‐resource countries

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